Filtration system and method for obtaining a cytology layer

ABSTRACT

A filter assembly for separating and collecting a layer of particulate matter (e.g., cells) from a liquid containing the particulate matter (e.g., a biological fluid specimen). The filter assembly has a holder and contiguous inner and outer fluid pervious media. The outer fluid pervious medium is attached to the sidewall of the holder. The inner fluid pervious medium is of low fluidic impedance relative to the outer fluid pervious medium. The filter assembly is designed for use in a separation housing that defines two flow paths between inlet and outlet, one directly through the filter and the other around the periphery of the filter. The inlet portion of the housing has a central inlet in a radially sloped surface that faces the filter collection site. A movable suction head is adapted to cooperate with the housing and the filter assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of commonly owned U.S.provisional application Nos. 60/330,092, filed Oct. 19, 2001,60/372,080, filed Apr. 15, 2002, and 60/373,658, filed Apr. 19, 2002,all of which are incorporated herein by reference. This application alsois related to commonly owned U.S. non-provisional application No.10/122,151, filed Apr. 15, 2002, which is also incorporated herein byreference.

TECHNICAL FIELD

[0002] The present disclosure is directed to apparatus and methods forcollecting and processing specimens of particulate matter-containingliquid, e.g., biological fluid, including collecting and depositing ontoa microscope slide or other surface a uniform layer of particulatestherefrom (e.g., cells) suitable for examination (e.g., use in cytologyprotocols).

BACKGROUND ART

[0003] Diagnostic cytology, particularly in the area of clinicalpathology, bases cytological interpretations and diagnoses onexamination of cells and other microscopic objects. The accuracy of thescreening process and diagnosis, and the preparation of optimallyinterpretable samples from specimens typically depends upon adequatespecimen and sample preparation. In this regard the ideal sample wouldconsist of a monolayer of substantially evenly spaced cells, whichenables cytotechnologists, cytopathologists, other medicalprofessionals, and automated screening and diagnostic equipment to viewor image the cells more clearly so that abnormalities can be identifiedmore readily, more accurately and more reproducibly. Newer methodologiessuch as immunocytochemistry and cytometric image analysis requirepreparation apparatus and methods that are safe, effective, accurate,precise, reproducible, inexpensive, efficient, fast and convenient.

[0004] Cytological examination of a sample begins with obtainingspecimens including a sample of cells from the patient, which cantypically be done by scraping, swabbing or brushing an area, as in thecase of cervical specimens, or by collecting body fluids, such as thoseobtained from the chest cavity, bladder, or spinal column, or by fineneedle aspiration or fine needle biopsy. In a conventional manualcytological preparation, the cells in the fluid are then transferreddirectly or by centrifugation-based processing steps onto a glassmicroscope slide for viewing. In a typical automated cytologicalpreparation, a filter assembly is placed in the liquid suspension andthe filter assembly both disperses the cells and captures the cells onthe filter. The filter is then removed and placed in contact with amicroscope slide. In all of these endeavors, a limiting factor in thesample preparation protocol is adequately separating solid matter fromits fluid carrier, and in easily and efficiently collecting andconcentrating the solid matter in a form readily accessible toexamination under a microscope.

[0005] Currently, biological specimens are collected for cytologicalexaminations using special containers. These containers usually containa preservative and transport solution for preserving the cytologyspecimen during shipment from the collection site to the diagnosticcytology laboratory. Further, cytology specimens collected from the bodycavities using a swab, spatula or brush are also preserved in specialcontainers with fixatives (e.g., alcohol or acetone fixatives) prior totransferring cells onto the slide or membrane for staining orexamination. Specimen containers are known that allow a liquid-basedbiological specimen to be processed directly in the container so as toobtain a substantially uniform layer of cells on a collection site (in afilter housing defining a particulate matter separation chamber) that isassociated with the container itself. See, for example, U.S. Pat. Nos.5,301,685; 5,471,994; 6,296,764; and 6,309,362, of Raouf A. Guirguis,all of which are incorporated herein by reference.

[0006] The filtration techniques taught in these patents in practicehave yielded fairly good results in terms of obtaining close to amonolayer of cells on slides, but there is room for improvement.Further, the types of specimen containers disclosed in these patentsrequire specially configured apertured covers and adapters therefor thatare designed to mate with the filter housing, and with suction equipment(e.g., a syringe or a mechanized vacuum source) used to aspirate liquidfrom the container and draw it through the filter. In addition,extraction of the filter so that it can be pressed against a microscopeslide to transfer collected cells to the slide requires disassembly ofthe cooperating parts of the cover and/or adapters associated therewith.If the processing is done by automated equipment, special handlingdevices are required to carry out such disassembly. All of thiscomplexity adds time, and material and labor cost to the processingrequired prior to the actual cytology examination.

[0007] In general, automated equipment thus far developed for processingliquid-based specimens have not performed with sufficient consistency,reliability, speed and automation to satisfy current and projected needsin cancer screening and other cytology-based medical, analytical,screening and diagnostic procedures. The vial-based automated processingsystem disclosed herein provides a safe, elegant and effective solutionto these problems.

SUMMARY DISCLOSURE OF THE INVENTION

[0008] The specimen vial disclosed herein houses a complete processingassembly, typically one for mixing the liquid-based specimen therein andfor holding a filter on which a uniform layer of cells can be collectedfrom the specimen. It is expected that the specimen vial would beprepackaged with a liquid preservative solution, as is commonplace, andsent to the point-of-care site for specimen collection.

[0009] The processing assembly is coupled to a simple cover for the vialby means of a simple and inexpensive releasable coupling. When the coveris removed at the point-of-care site (physician's office, clinic,hospital, etc.), the processing assembly remains with the cover to allowmedical personnel easy access to the container interior for insertion ofa biological specimen into the vial. The cover, along with the attachedprocessing assembly, is then replaced to seal the vial. The vial maythen be sent to a laboratory for processing.

[0010] When the vial is manipulated in a simple way while still closed,the processing assembly detaches from the cover and remains in the vialfor access by automated or manual laboratory equipment when the cover issubsequently removed. In a preferred embodiment, a downward force on thecenter of the cover is all that is required to detach the processingassembly from the cover. In contrast with the prior art specimen vialsdiscussed above, the vial of the present invention requires no furtherinteraction with the cover, which can be removed by a simple uncappingdevice and is discarded to avoid contamination. Ribs inside the vialsupport the processing assembly in the proper position for access duringprocessing. This self-contained vial and processing assembly arrangementminimizes human operator exposure to biohazards, such as tuberculosis orother pathogens in sputum or in other specimens types, such as urine,spinal tap fluid, gastric washings, fine-needle aspirates, andgynecological samples.

[0011] The automated specimen processing apparatus disclosed herein isreferred to as the “LBP” device (for liquid-based preparation), and isdesigned to produce slides of high quality and consistency. The LBPdevice also can be interfaced with a device for detecting and/orquantifying multiple morphologic, cytochemical, and/or molecular changesat the cellular level.

[0012] During the past two years or so, a review of the literature andreanalysis of existing data have led to the identification of a panel ofmolecular diagnostic reagents that are capable of detecting andcharacterizing lung cancer, which is the most common cancer, with highsensitivity and specificity. See, for instance, commonly owned U.S.patent application Nos. 10/095,297 and 10/095,298, both filed Mar. 12,2002, and No. 10/241,753, filed Sep. 12, 2002. Here, the cells can bereacted with antibodies and or nucleic-acid “probes” that identify apattern of changes that is consistent with a diagnosis of cancer. Themolecular system can utilize algorithms fine tuned for that tumorheterogeneity.

[0013] Identifying molecular changes at the cellular level is one of theways cancer can be detected early and at a more curable stage. Suchmolecular diagnostic devices can be used for early detection anddiagnosis with the necessary sensitivity and specificity to justifytheir use as population-based screens for individuals who are at-riskfor developing cancer. Such a molecular diagnostic device also can beused to characterize the tumor, thereby permitting the oncologist tostratify his/her patients, to customize therapy, and to monitor patientsin order to assess therapeutic efficacy and disease regression,progression or recurrence. The availability of such tests will alsofoster the development of new and more effective therapeutic approachesfor the treatment of early stage disease.

[0014] Such molecular diagnostics are designed to balance cost and testperformance. While screening tests must exhibit high sensitivity andspecificity, cost is always a critical factor, as the tests aretypically directed to performing on a large number of individuals who,while at-risk, do not typically have symptomatic evidence of thedisease. In this respect, the present LBP device can be interfaced witha molecular diagnostic device to develop a system for automaticallydiagnosing cancer, with a minimum or no human intervention.Alternatively, the present LBP device can be interfaced with a pathologywork station, where medical professionals can observe individual slidesprepared by the LBP device. The resulting diagnosing system, regardlesswhether an automated device or a manual observation device isinterfaced, can be interfaced with an integrated data management systembased on specialized software and a computer operating system to managedata entry and exchange of information, and network with the laboratoryand hospital information systems.

[0015] The present LBP device transports multiple specimen vials of thenovel type mentioned above sequentially through various processingstations and produces fixed specimens on slides, each slide beingbar-coded and linked through a data management system to the vial andthe patient from which it came. Fresh slides are automatically removedone at a time from a cassette, and each is returned to the same cassetteafter a specimen is fixed thereon. Multiple slide cassettes can beloaded into the LBP device, and the device will automatically draw freshslides from the next cassette after all of the slides of the precedingone have been used. The slide cassettes preferably are configured forliquid immersion and interfacing with automated staining equipment thatwill stain the specimens without having to remove the slides from thecassette. In this regard the cassettes preferably have slots that allowfor liquid drainage, and slots or other means that cooperate with thehooks normally used in the staining equipment to suspend other types ofslide holders. The same slide cassettes are also configured to interfacewith automated diagnostic equipment and other devices that are part ofan integrated system.

[0016] While specimen vials can be loaded into the transport manually,the full benefits of automation can be realized by using an optionalvial handling system that automatically loads specimen vials forprocessing, and removes each one after its processing is complete. Inone example of such a handling system the vials initially are loadedmanually into special space-saving trays that hold up to forty-one vialseach. Up to eight trays can be loaded into the LBP device, and thedevice will process all of them sequentially, removing one at a timefrom a tray and returning processed (and resealed) vials to a tray. Thetrays also can be used for storing and retrieving processed vials.

[0017] Each vial is transported through the LBP device on acomputer-controlled conveyor, in its own receptacle. (In the exampledisclosed the conveyor has thirty receptacles.) The vials and thereceptacles are keyed so that the vials proceed along the processingpath in the proper orientation, and cannot rotate independently of itsrespective receptacle. They first pass a bar code reader (at a dataacquisition station), where the vial bar code is read, and then proceedstepwise through the following processing stations of the LBP device: anuncapping station including a cap disposal operation; a primary mixingor dispersal station; a filter loading station; a specimen acquisitionand filter disposal station; a cell deposition station; and a re-cappingstation. There is also a slide presentation station, at which a freshmicroscope slide is presented to the specimen acquisition station fortransfer of the specimen to the slide. Each of the stations operatesindependently on the vial presented to it by the conveyor, but theconveyor will not advance until all of the operating stations havecompleted their respective tasks.

[0018] The vial uncapping station has a rotary gripper that unscrews thecover from the vial, and discards it. Before doing so, however, theuncapping head presses on the center of the cover to detach the internalprocessing assembly from the cover. The primary mixing station has anexpanding collet that grips the processing assembly, lifts it slightlyand moves (e.g., spins) it in accordance with a specimen-specificstirring protocol (speed and duration). The filter loading stationdispenses a specimen-specific filter type into a particulate matterseparation chamber (manifold) at the top of the processing assembly. Thespecimen acquisition station has a suction head that seals to the filterat the top of the processing assembly and first moves the processingassembly slowly to re-suspend particulate matter in the liquid-basedspecimen. Then the suction head draws a vacuum on the filter to aspiratethe liquid-based specimen from the vial and past the filter, leaving amonolayer of cells on the bottom surface of the filter. Thereafter themonolayer specimen is transferred to a fresh slide, and the vial movesto the re-capping station, where a foil seal is applied to the vial.

[0019] An improved filter system ensures that the highest qualitymonolayer specimens are produced. Specimen liquid flows through thefilter as well as substantially across the front surface of the filter.Specifically, the specimen liquid is made to have a secondary flowcomponent across the filter surface. The secondary flow is designed toflow radially outwardly or have a substantial radial component, whichcreates a shearing action that flushes or washes clusters of relativelyweakly adhering particulates so that a more uniformly distributed andthinner layer can be formed on the front surface of the filter. In thisrespect, the present system includes a peripheral outlet through whichspecimen liquid can flow from the area adjacent the front surface of thefilter.

[0020] The filter assembly preferably has a holder, a frit seated in theholder, and a membrane filter positioned over and in contact with theouter surface of the frit. The frit can extend beyond the end of theholder. The membrane filter can be attached to the holder. The sidewallportion extending beyond the holder forms an area through which thespecimen liquid can flow, creating a secondary flow. The holder can beconfigured so that the frit is slightly bowed outwardly at the center sothat when pressure is applied to a slide during the specimentransferring step, the central portion of the frit flattens to moreevenly contact the membrane filter to the slide for more effectivetransfer.

[0021] The manifold at the upper end of the processing assembly seatsthe filter assembly with the membrane filter side facing down. Themanifold preferably has a substantially conically configured bottom wallthat rises from the central inlet (which communicates with the dependingsuction tube portion of the processing assembly). The filter assemblyand the conically configured bottom wall form a manifold chamber thathas a slight gap at its periphery, forming a peripheral outlet, byvirtue of raised members or standoffs that act as spacers. The standoffscan have channels between them through which the specimen liquid canflow out of the manifold chamber.

[0022] Various preferred materials and possible alternatives arespecified herein for several components of the system. It is to beunderstood that material choices are not limited to the specificmaterials mentioned, and that the choice of an alternate material isgoverned by many factors, among them functionality, molding accuracy,durability, chemical resistance, shelf life, cost, availability, and/oroptical clarity (e.g., to address user requirements or marketingissues).

[0023] One aspect of the invention claimed herein is a filter assembly(holder, inner fluid pervious medium and outer fluid pervious medium)for separating and collecting a layer of particulate matter from aliquid containing the particulate matter. The holder has a base and asurrounding sidewall projecting from the base, the base and the sidewalldefining an open cavity extending from the base to the rim of thesidewall. The inner fluid pervious medium is held in the cavity and hasopposed inner and outer faces, the inner face facing the base. A flowopening in the holder is in fluid communication with the inner face ofthe inner fluid pervious medium. The outer fluid pervious mediumoverlies the outer face of the inner fluid pervious medium and isattached to the sidewall. The exposed face of the outer fluid perviousmedium is adapted to collect a layer of the particulate matter. Theinner fluid pervious medium is of low fluidic impedance relative to theouter fluid pervious medium so that the pressure drop across the innerfluid pervious medium is less than the pressure drop across the outerfluid pervious medium when liquid flows therethrough.

[0024] The inner fluid pervious medium preferably is proud of the rim ofthe holder. The rim of the holder preferably is chamfered, and the outerfluid pervious medium preferably comprises a membrane filter fused tothe chamfer.

[0025] Another aspect of the invention is an apparatus for separatingand collecting a layer of particulate matter from a liquid containingthe particulate matter. A housing defines a separation chamber having aninlet portion and an outlet portion. A filter in the housing has acollection site facing the inlet portion and defines two flow pathsbetween the inlet portion and the outlet portion. One flow path isdirectly through the filter and the other flow path is around theperiphery of the filter. The inlet portion has a central inlet in asurface that faces the collection site, and is radially sloped such thatthe distance between the sloped surface and the collection sitedecreases from the inlet toward the periphery of the filter. Liquidintroduced to the separation chamber through the inlet thus flowsdirectly through the filter to deposit a layer of particulate matter onthe collection site, and also flows with particulate matter outwardlyacross the collection site toward the edge of the filter to wash excessparticulate matter from the collection site.

[0026] A further aspect of the invention is a method for collectingcells for cytology, comprising passing a biological fluid containingcells through a separation chamber having therein a filter with a cellcollection site positioned transversely of the fluid flow path enteringthe separation chamber through a centrally located inlet, and divertinga portion of the fluid flow outwardly toward the periphery of the filterby juxtaposition of an inlet surface adjacent the collection site thatis radially sloped such that the distance between the sloped surface andthe collection site decreases from the inlet toward the periphery of thefilter. Fluid introduced to the separation chamber through the inletthus flows directly through the filter to deposit cells on thecollection site, and also flows outwardly across the collection sitetoward the edge of the filter to wash away excess cells from thecollection site leaving substantially a monolayer of cells on thecollection site.

[0027] Yet another aspect of the invention is a method for collectingcells from individual specimens of biological fluid in specimencontainers. Each container has therein a processing assembly comprisingan open-top separation chamber, adapted to receive a filter assemblyhaving a downwardly facing collection site, and a depending aspirationtube that extends into the specimen and communicates with the separationchamber through the bottom wall thereof. The method entails, for eachcontainer, the steps of placing a filter assembly in the separationchamber; coupling a movable suction head to the processing assembly andthe filter assembly; elevating the suction head to raise the processingassembly sufficiently to eliminate contact of the processing assemblywith the container; applying a vacuum to the filter assembly to aspiratespecimen fluid from the container through the tube, into the separationchamber and through the filter until a layer of cells is collected onthe filter collection site; uncoupling the suction head from theprocessing assembly; and elevating the suction head to remove thestill-coupled filter assembly from the separation chamber.

[0028] Still another aspect of the invention is an apparatus forcarrying out the above cell collecting method. The above-referencedsuction head is adapted to be positioned above a container and mountedfor vertical movement relative to the container. The suction head hascoaxial inner and outer portions, the outer portion having an annularskirt adapted to surround and sealingly engage the annular wall of theseparation chamber, and the inner portion having a lower face with anaspiration suction port and a retention suction port. The inner portionis mounted for axial movement relative to the outer portion and isadapted to sealingly engage the upper face of the holder so that theaspiration suction port is in fluid communication with the flow openingand the retention suction port is in fluid communication with a sealedannular area on the upper face of the holder. A head actuator moves thesuction head vertically, and an inner portion actuator separately movesthe inner portion vertically. The suction head may be rotatable so as tomix the specimen in the container. It may also be mounted for lateralmovement away from and toward the container.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0029] Preferred embodiments of the disclosed system and the invention,including the best mode for carrying out the invention, are described indetail below, purely by way of example, with reference to theaccompanying drawing, in which:

[0030]FIG. 1 is a vertical sectional view through a specimen vial foruse with the LBP device, showing the processing assembly (stirrer) inthe vial coupled to the cover;

[0031]FIG. 2a is a front elevational view of the container portion ofthe vial;

[0032]FIG. 2b is a top plan view of the container, shown with thestirrer removed;

[0033]FIG. 3 is a top plan view of the stirrer;

[0034]FIG. 4 is a bottom plan view of the liner that fits within thecover;

[0035]FIG. 5 is an exploded vertical sectional view of the stirrer and afilter assembly adapted for use in the stirrer;

[0036]FIG. 6 is a vertical sectional view of the upper portion of thestirrer, showing the filter assembly in place in the particulate matterseparation chamber;

[0037]FIG. 7a is a partial schematic view of the arrangement depicted inFIG. 6, showing the flow of liquid and particulate matter separatedtherefrom;

[0038]FIG. 7b is a view similar to FIG. 7a, showing liquid flow in aprior art filter system;

[0039]FIG. 8 is an exploded, cross-sectional view of the filterassembly;

[0040]FIG. 9 is a schematic illustration of the dimensionalconfiguration of the flow manifold;

[0041]FIG. 10 is a vertical sectional view of the specimen vial similarto FIG. 1, but showing the stirrer detached from the cover;

[0042]FIG. 10a is a partial vertical sectional view similar to FIG. 10,showing a modification of the stirrer;

[0043]FIG. 11 is a top plan view of the LBP device;

[0044]FIG. 11a is a schematic diagram of the operating sequence of theLBP device;

[0045]FIG. 12 is a front perspective view of the LBP device, withcertain parts removed for clarity;

[0046]FIG. 13 is a rear perspective view of a portion of the LBP device,showing the auto loader/unloader mechanism;

[0047]FIG. 14 is a top plan view of the auto loader/unloader mechanism;

[0048]FIG. 15 is a front elevational view of the auto loader/unloadermechanism;

[0049]FIG. 15a is a detail sectional view taken along line 15 a-15 a inFIG. 14;

[0050]FIG. 16 is an elevational view of an alternative embodiment of agripper for the auto loader/unloader mechanism;

[0051]FIG. 17 is a perspective view of a specimen vial tray used in theauto loader/unloader mechanism;

[0052]FIG. 18 is an enlarged detail view taken at encircling line 18 inFIG. 17;

[0053]FIG. 19 is a bottom perspective view of the specimen vial tray ofFIG. 17;

[0054]FIG. 20 is a perspective view of three stacked specimen vialtrays;

[0055]FIG. 21 is a block diagram showing specimen vial handling and dataflow;

[0056]FIG. 21a is a pictorial diagram showing an overall laboratorysystem incorporating the LBP device;

[0057]FIG. 21b is a relational database table;

[0058]FIG. 22 is a block diagram showing a computer or work station;

[0059]FIG. 23 is a facsimile of a computer screen;

[0060]FIG. 24 is a facsimile of another computer screen;

[0061]FIG. 25 is a facsimile of two computer screens;

[0062]FIG. 26 is a vertical sectional view of a specimen vial beinguncapped;

[0063]FIG. 27 is a front elevational view, partly in section, of aspecimen vial engaged by the uncapping head of the LBP device;

[0064]FIG. 28 is a top plan view of the uncapping head, taken along line28-28 in FIG. 27;

[0065]FIG. 29 is a side elevational view of the uncapping station of theLBP device;

[0066]FIG. 30 is a sectional view taken along line 30-30 in FIG. 29;

[0067]FIG. 31 is a top plan view of the uncapping station of FIG. 29;

[0068]FIG. 32 is a vertical sectional view of a specimen containershowing engagement by the primary stirring head;

[0069]FIG. 33 is a side elevational view of the primary stirring stationof the LBP device;

[0070]FIG. 34 is a front elevational view of the primary stirringstation;

[0071]FIG. 35 is a top plan view of the primary stirring station;

[0072]FIG. 36 is a vertical sectional view of a specimen containerduring filter loading;

[0073]FIG. 37 is a side elevational view of the magazine portion of thefilter loading station of the LBP device;

[0074]FIG. 38 is a front elevational view of the pusher portion of thefilter loading station;

[0075]FIG. 39 is a top plan view of the pusher portion of the filterloading station;

[0076]FIG. 40 is a top plan view of the magazine portion of the filterloading station;

[0077]FIG. 41 is a vertical sectional view of a specimen containerduring specimen acquisition;

[0078]FIG. 42 is a vertical sectional view of a specimen containerduring specimen transfer to a slide;

[0079]FIG. 43 is a side elevational view of the specimen acquisitionstation of the LBP device;

[0080]FIG. 44 is a front elevational view of the lower portion of thespecimen acquisition station;

[0081]FIG. 45 is a top plan view of the specimen acquisition station,partly in section, taken along line 45-45 in FIG. 43;

[0082]FIG. 46 is a top plan view of the specimen acquisition station;

[0083]FIG. 47 is a schematic of a bubble flow meter used in the specimenacquisition station;

[0084]FIG. 47a is a schematic of a modification of the flow meter ofFIG. 47;

[0085]FIG. 48 is a schematic of a vacuum system used in the specimenacquisition station;

[0086]FIG. 49 is an operation chart for the vacuum system of FIG. 48;

[0087]FIG. 50 is a front perspective view of the re-capping station ofthe LBP device;

[0088]FIG. 51 is a side elevational view of the re-capping station;

[0089]FIG. 52 is a front perspective view of a slide cassette used inthe LBP device;

[0090]FIG. 53 is a detail perspective view of the slide cassette takenfrom FIG. 52;

[0091]FIG. 54 is a rear perspective view of the slide cassette;

[0092]FIG. 55 is a side elevational view of the slide cassette;

[0093]FIG. 56 is a top plan view of the slide presentation system of theLBP device; and

[0094]FIG. 57 is a side elevational view of the slide presentationsystem.

DETAILED DESCRIPTION OF BEST MODE

[0095] A full description of this vial-based specimen handling andprocessing system must begin with the vial itself, which consists of acontainer, a cover and a processing assembly (stirrer) in the vial.

[0096] Specimen Vial

[0097] Referring to FIGS. 1, 2a and 2 b, the vial 10 comprises acontainer 20, a cover 30 and a processing assembly 40. Processingassembly 40 is designed to carry out several functions, among themmixing, and for this preferred rotary embodiment will be referred to asa stirrer for the sake of convenience. Container 20 preferably is moldedof a translucent plastic, preferably polypropylene, and has asubstantially cylindrical wall 21, surrounding its longitudinal axis,joined to a conical bottom wall 22. Possible alternative plasticsinclude ABS and polycyclohexylenedimethylene terephthalate, glycol(commercially available from Eastman Kodak Co. under the name EASTAR®DN004). A small portion 24 of wall 21 preferably is flat, the outersurface of the flat portion adapted to receive indicia, e.g., a bar codelabel, containing information concerning the specimen placed in thevial. Although only one flat portion is shown, the container could beconfigured without a flat portion, or with two or more flat portions,each adapted to receive indicia. Alternatively, the indicia could belocated on a curved portion of wall 21. The bottom end of flat portion24 has an arcuate notch 25 which acts to keep the container in a properorientation when handled by the LBP device, which as noted is designedto cradle the container and move it through various processing stations.A differently shaped notch (e.g., V-shaped) can be used as long as thenotch properly mates with the LBP device. Other suitable matingstructures can be used instead.

[0098] Four longitudinal ribs 26 project inwardly from wall 21. Theupper ends 27 of ribs 26 form rests for the stirrer 40 when it isdetached from cover 30 (see FIG. 10). The top of container 20 has anopening 28 and a standard right-hand helical thread 29 that preferablyextends for one and one half turns and mates with a similar thread oncover 30. Other types of cover-to-container coupling may be used, suchas a bayonet coupling, snap-fit arrangement, etc.

[0099] Cover 30 comprises a commercially available simple molded plasticthreaded cap 31, and a novel liner 32 retained in the cap. Cap 30preferably is molded of polypropylene, but ABS and EASTAR® DN004, amongothers, are alternative plastic material choices. Cap 31 has a flatsolid top, and an externally knurled depending flange with an internalhelical thread 33 that mates with thread 29 on container 20. Referringto FIG. 4, liner 32 is molded of plastic material, preferablypolyethylene, and has a substantially flat base 34 sized to fit snuglywithin cap 31, behind thread 33, so that the liner is not readilyseparated from the cap. As seen in FIG. 1, liner base 34 serves as agasket-type seal between the cap 31 and the rim of the container wall21.

[0100] Liner base 34 has a coupler in the form of an annular projection35 that preferably is slightly conical in shape, preferably forming anangle of about 5° to its central axis. In other words, the innerdiameter of annular coupler 35 is greater at its proximal end, where itjoins liner base 34, than at its distal end. Liner base 34 also has acentral annular boss 36 that projects further from base 34 than annularcoupler 35 so as to interact with stirrer 40, as described below. Whilethe use of a separate liner mated to a standard cap is preferred, thecover could be integrally molded in one piece to include the annularcoupler 35 and the central annular boss 36. Such a one-piece cover (oreven the two-piece cover described above) could instead be configured toact as a plug-type seal by projecting into and sealing against theinside of the rim of container wall 21.

[0101] Referring to FIGS. 1, 3 and 5, stirrer 40 is molded of plastic,preferably polypropylene, and has a circular base or bottom wall 41,sloped at its center, with a central inlet port 42; a central dependingsuction tube 43 with two diametrically opposed suction ports 44 near thebottom of the tube; and a dispersing (mixing) element in the form oflaterally extending vanes 45. The upper portion of the stirrer 40 has acup-shaped particulate matter separation chamber or manifold 46 definedby base 41 and an upstanding annular wall 47. The upper edges of wall 47are beveled, the inner edge 48 preferably being beveled to a greaterdegree to facilitate placement of a filter assembly F in manifold 46, asdescribed below. Possible alternative plastic material for the stirrerinclude ABS and EASTAR® DN004.

[0102] Annular wall 47 serves as a coupler for releasably coupling thestirrer 40 to cap liner 32, and is therefore dimensioned to fit snuglywithin annular coupler 35 (see FIG. 1). Specifically, there is afriction or press fit between couplers 35 and 47 such that normalhandling of the closed vial, and normal handling of cover 30 whenremoved from container 20 (e.g., to place a biological specimen in thecontainer) will not cause separation of the stirrer from the cover.Coupler 47 is dimensioned relative to coupler 35 so that there is a veryslight initial diametrical interference, preferably about 0.31 mm.Coupler 47 is stiffer than coupler 35, so assembly of the stirrer to thecover involves slight deformation principally of coupler 35, resultingin a frictional force that keeps the stirrer and the cover engaged.Application of an external force to the vial that overcomes thisfrictional retention force will cause stirrer 40 to detach from cover 30and drop by gravity further into container 20 (see FIG. 10).

[0103] The external separation force preferably is applied to thecentral portion of cover 30 (see the arrow in FIG. 10), which deflectscap 31 and liner 32 inwardly. As illustrated in FIG. 1, central boss 36on liner 32 is dimensioned such that its distal end just contacts orlies very close to base 41 of the stirrer. Thus, when the centralportion of the cover is depressed, central boss 36 will deflect furtherthan annular coupler 35 on liner 32 and push stirrer 40 out ofengagement with coupler 35. Inward deflection of liner 32 also causescoupler 35 to spread outwardly, thereby lessening the retention forceand facilitating detachment of the stirrer. The separation force appliedto cover 30 and required to detach the stirrer should be in the range of5 to 30 lbs., preferably about 12 lbs.

[0104] Once detached from the cover 30, stirrer 40 comes to rest on theupper ends 27 of ribs 26. See FIG. 10. The particulate matter separationchamber (manifold) 46 thus is stably supported near the containeropening and easily accessed by the LBP processing heads, which willmanipulate the stirrer so as to process the specimen directly in thecontainer. At least three ribs 26 are required to form a stable supportfor the stirrer, but four are preferred because that number seems topromote more thorough dispersion of the particulate matter in the liquidduring stirring. Should the stirrer inadvertently become detached fromthe cover at the point-of-care site, the physician or an assistantsimply places the stirrer loosely in the vial so that it descends intothe specimen and then screws the cover on as usual. This is notdifficult because the ribs in the vial allow insertion of the stirrer inonly one direction. Once the vial is closed with the specimen inside,the stirrer remains in the vial throughout processing and is sealedtherein when the vial is recapped.

[0105] A small percentage of patient specimens, as may be found ingynecological Pap test and other specimen types, contain large clustersof cells, artifacts, and /or cellular or noncellular debris. Some ofthese large objects, if collected and deposited on a slide, can obscurethe visualization of diagnostic cells and, consequently, result in aless accurate interpretation or diagnosis of the slide sample. Sincemost of these features are not of diagnostic relevance, theirelimination from the sample is, in general, desirable. To achieve thisresult, the side suction ports 44 in the stirrer suction tube 43preferably are eliminated (see FIG. 10a) in favor of close control ofthe interface between the bottom of the suction tube 43 and the smallprojection 23 at the center of bottom wall 22 of the container 20. Thisinterface effectively forms a metering valve whose geometry (orifice) 23a is created when the stirrer 40 rests on the ribs 26 of the container20 (see FIG. 10). Proper sizing of the annular flow orifice 23 aprevents large objects from entering the suction tube 43, while allowingthe passage of smaller objects that may be diagnostically useful. Whilethe orifice 23 a has a thin passage section and a small metering area,clogging is not an issue due to its large diameter. The annular orifice23 a preferably has an outside diameter on the order of 0.105 in. and aninside diameter on the order of 0.071 in., yielding a passage width onthe order of 0.017 in. This orifice size is optimized for gynecologicalspecimens.

[0106] Filter System

[0107]FIGS. 6 and 8 illustrate one embodiment of a filter assembly Faccording to the present invention. FIGS. 3 and 6 illustrate oneembodiment of a manifold 46 (in stirrer 40) according to the presentinvention. The filter system includes the filter assembly F and themanifold 46.

[0108] Referring to FIGS. 6 and 8, the filter assembly F comprises afilter housing or holder 200, a porous frit 202, and a porous membranefilter 205. FIG. 8 shows these components more clearly in an explodedview. The holder 200 can be cup- or container-shaped, having a recess orcavity 206 for seating the frit 202 and a chamber 207 between the frit202 and the holder 200. The frit 202 and the membrane filter 205 can bemade of the materials disclosed in the Guirguis patents identifiedabove, namely U.S. Pat. Nos. 5,301,685 and 5,471,994, the disclosures ofwhich are incorporated herein by reference.

[0109] In the present filter assembly F the membrane filter 205, thefrit 202, and the holder 200 are assembled together as a unit. The frit202, which has a cylindrical shape, is first seated in the holder 200.Then the membrane filter 205 is permanently affixed, adhered, joined, orfused to the holder 200. In the illustrated embodiment, the outerperimeter or edge of the membrane filter 205 is fused to the holder 200.In this regard, the holder 200 has a bevel or chamfer 208 formed aroundan outer circumferential corner 209. The chamfer 208 provides an angledsurface to which the membrane filter 205 can be attached using aconventional bonding technique, such as ultrasonic welding. The holder200 and the membrane filter 205 should be made of materials that willfuse together. Preferably both are made of polycarbonate, although anABS holder will work with a polycarbonate membrane filter. Thermoplasticpolyester could be used for the holder if the membrane filter is made ofthe same material. The frit 202 preferably is made of polyethylene.

[0110] Referring to FIG. 8, the holder 200 preferably is cylindrical andcomprises a substantially cup-shaped body having a bottom wall or base210 and a substantially upright cylindrical sidewall 211 extendingtherefrom and terminating in a rim 211 a. The sidewall 211 has anannular shoulder 212 extending radially inwardly, toward the center. Theshoulder 212 acts as a seat that accurately positions the frit 202. Frit202 preferably is dimensioned so that the frit's outer or front face 213is proud of (extends beyond) the rim 211 a when the peripheral portionof the frit's rear face abuts the shoulder 212.

[0111] The inner diameter of the sidewall 211 can be dimensioned tofrictionally engage and hold the frit 202 in place. In this respect, thefrit's outer diameter can substantially correspond to the inner diameterof the sidewall 211 to mechanically, i.e., frictionally, hold the frit202 in place. However, since the membrane filter 205 covers the frit202, the frit need not be frictionally held to the holder. That is, thefrit 202 can be loosely seated in the holder. Frictionally seating thefrit 202 in the holder 200, however, maintains the frit 202 in place sothat attachment of the member filter 205 can be done at a remote site.It also simplifies and reduces the cost of mass production of filterassemblies because the holder 200 and the frit 202 can be joined to makea secure subassembly and stored for later attachment of the membranefilter 205.

[0112] After the frit 202 is seated in the holder 200, the membranefilter 205 is draped over the frit's outer face 213 and the exposedportion 214 of the frit's side wall 215 that extends beyond the holder200, and is attached to the chamfer 208, as is better seen in FIG. 6.The frit's exposed outer sidewall portion 214 provides an annularsurface area through which the specimen liquid can flow to provide adual flow path, as schematically illustrated in FIG. 7a.

[0113] The filter assemblies F can be coded to denote different poresize and pore density (number of pores per unit cross-sectional area) asmay be required for specific processing protocols. Color coding offilter assemblies is preferred, although any form of machine-detectablecoding can be used, including distinguishing projections, such as smallnipples, for tactile-based sensor recognition. The LBP device isprovided with a sensor that can discriminate between these colors orother codes to ensure proper filter selection. The filter assembliesalso can be provided in paper carriers for easy insertion into the LBPdevice.

[0114] Referring back to FIG. 8, the holder's bottom wall 210 has acentral opening 204 through which vacuum can be applied to draw specimenliquid therethrough. The holder 200 further includes a centralprojection or protrusion 216 extending into the holder from the bottomwall 210. The central protrusion 216 is aligned with the opening 204 andpositioned in the chamber 207, which is defined by the frit's inner face218, the inner face 219 of the bottom wall 210 and the inner side 220 ofthe sidewall 211. The protrusion 216 is substantially hollow and has aplurality of side openings 221 that distribute vacuum to the chamber 207and provide a substantially symmetrical flow through the chamber. Thespecimen liquid drawn through the membrane filter 205 and the frit 202fills the chamber 207 and exits the chamber 207 through the sideopenings 221 and the central opening 204.

[0115] The protrusion 216 has an abutting surface 217 that faces andextends toward the holder's open face. The abutting surface 217 isconfigured to abut against the frit's rear face 218. In particular, theabutting surface 217 is slightly proud of the annular shoulder 212. Thatis, the abutting surface 217 lies slightly above or beyond the level ofthe annular shoulder 212 so that the frit's outer face 213 bows slightlyoutwardly when the frit is installed in the holder. For example, theabutting surface 217 can extend beyond the height of the annularshoulder 212 by about 0.002 inch. The resulting slight bow created bythe protrusion pushing out the central portion of the frit 202 ensuresthat the central part of the membrane filter 205 contacts the slide. Thepressure applied to the slide during imprinting flattens the frit'sfront surface 213, ensuring full contact of the membrane filter 205 withthe slide to more effectively transfer the collected particulates to theslide and minimizing any deposition artifacts. If this slightly bowedconfiguration is desired, the frit 202 preferably is securely seated inthe holder 200, such as by friction as previously explained.

[0116] Due to the bowed frit configuration, the membrane filter 205 neednot be taut. This simplifies the manufacturing process, reduces cost,and reduces the rejected part rate.

[0117] Anything short of a major wrinkle can work effectively. As noted,the frit 202 preferably is slightly deformable, its compliance allowingit to flex and flatten against a glass slide post aspiration to transfercells and other objects of interest from the filter to the slide. Toaccomplish this the frit should have an elasticity that allows it to becrushed flat by application of a force of 8 lbs. through a displacementof 0.0016 in. Good frit materials include sintered polyethylene andsintered polyester. The frit 202 may be a porous material, withspatially random pores, typically with pore sizes in the range of about50-micrometer to 70-micrometer. A significant attribute of this materialis that it is of low fluidic impedance relative to the material of thethin membrane filter 205 (which typically has pore sizes of about5-micrometer to 8-micrometer). In other words, the pressure drop acrossthe frit 202 is much less than the pressure drop across the membranefilter 205. Thus, fluid that passes through the filter flows freelythrough the frit. Alternatively, instead of having randomly positionedpores, the frit 202 may be made of a material or structure that has manyparallel channels of small (e.g., 50-micrometer to 70-micrometer) innerdiameters through which aspirated fluid and particulates may flow. Sucha parallel-channel arrangement would behave as an inner fluid-perviousmedium with an apparent low fluidic impedance. In fact, any material ordevice with the proper low fluidic impedance anddeformability/resilience characteristics may be used in the specimenacquisition station, whether it has pores or not.

[0118] It has been found that flowing the specimen liquid substantiallyor mostly in an axial direction, i.e., perpendicular to the membranefilter, can accumulate layers or clusters of particulates, asschematically illustrated in FIG. 7b, particularly if the vacuum isapplied through the membrane filter for a longer period than necessary.This can happen even with the Guirguis dual flow design, which providessome secondary flow components that are radially directed. See, forexample, FIGS. 4 and 12 of Guirguis' U.S. Pat. Nos. 5,471,994 and5,301,685. It seems that the secondary flow generated by thatconfiguration is insufficient to create an effective flushing, orshearing action across the membrane filter. An earlier Guirguis patent,namely U.S. Pat. No. 5,137,031, discloses a funnel- or cone-shapedmanifold. In that arrangement, however, there is no secondary radialoutflow at its periphery. As there is no flow other than directlythrough the filter itself, there is no substantial radial flowcomponent. Accordingly, the specimen liquid only flows substantiallyperpendicularly to the membrane filter.

[0119] Referring to FIG. 6, the inner diameter of the upright wall 47 ofthe manifold 46 at the top of stirrer 40 is dimensioned to be slightlylarger than the outer diameter of the filter assembly F, namely theholder's sidewall 211, so that the manifold 46 can receive and seat thefilter assembly F, with the membrane filter 205 facing down, asillustrated. The filter assembly F can be loosely seated in the manifold46. When the filter assembly F is seated in the manifold 46, the outerperipheral edge of the membrane filter 205 rests on the bottom wall 41.The bottom wall 41 is configured to have a well or recess that forms amanifold chamber M when the filter assembly F is seated in the manifold46. The chamber M is thus bounded by the outer surface of the membranefilter 205 and the upper surface 41S of the bottom wall 41.

[0120] The present dual flow arrangement solves the problem ofparticulate build-up or accumulation on the face of the membrane filter.This arrangement causes a shearing force or action across the front faceof the membrane filter that is sufficient to flush the particulatesaside and keep them from building up or layering. Built-up or layeredparticulates have a weaker bond to the layer underneath them as theybuild up, because the suction power decreases as the pores of themembrane filter 205 become covered with particulates. A shearing forceis created by imparting a tangential or substantially radial flowcomponent to the specimen liquid across the front face of the membranefilter 205. This flow component is substantially parallel to the frontface of the membrane filter, i.e., it is perpendicular to the built-updirection of the layers, and flushes the particulates radiallyoutwardly, away from the front face of the membrane filter.

[0121] To provide a secondary or radial flow path, the manifold 46 isconfigured to provide a small spacing or gap G (see FIG. 6) at theperiphery of the manifold chamber M, between the front face of themembrane filter 205 and the upper surface 41S of the bottom wall 41, toallow flushed particulates to exit the manifold chamber M, away from thefront face of the membrane filter. The gap G must be large enough toprevent the particulates from clogging it. That is, if the gap G is madetoo small for the particulates being filtered, the gap G can getclogged, cutting off the secondary flow. The minimum size of the gapultimately depends on the particulate size, the viscosity of thespecimen liquid, and the temperature of the specimen liquid. It has beendetermined that the gap G should be at least 0.004 in. to preventclogging by cellular particulates.

[0122] Referring to FIGS. 3 and 6, to create the gap G, which forms anoutflow nozzle, the bottom wall 41 of manifold 46 includes a pluralityof spaced standoffs or raised ribs 48 a around the periphery of themanifold 46. The spaces 49 between the ribs 48 a provide a passage forspecimen liquid to exit the chamber M. In the illustrated preferredembodiment, the manifold 46 has an inner diameter of 23.4 mm, and hasthirty-six ribs 48 a, evenly spaced at 10°. The ribs are 0.150 mm highand arcuately blend into the surrounding shoulder with a radius R of0.63 mm, as illustrated. Of course, the present invention contemplatesother configurations of spaced ribs or standoffs, which are intended toprecisely space the filter assembly from the bottom wall 41 so that aprecise outflow area is created. Depending on the number and thicknessof ribs or standoffs, the total outflow area can be reduced as much as50% as compared to the inlet area.

[0123] It has been observed in the Guirguis type filter arrangementreferred to above that specimen liquid traveling radially outwardlyloses velocity. The present dual flow filter system compensates for thevelocity slowdown by providing a shallow, substantially conical surfaceacross which the specimen liquid flows. This surface forms asubstantially conical distribution manifold chamber M confronting themembrane filter 205. The chamber M according to the present inventionhas an annular radial outlet O, through spaces 49, having an area thatis about equal to or smaller than the maximum area of the central inletI. Referring to FIG. 9, the “face” area of the radially directed annularflow passage is cylindrical and is defined (bounded) at any given radiusR₁, R_(x), R_(y), . . . , R₂ by the front surface of the membrane filter205 and the conical surface 41S of the manifold. As the specimen liquidtravels outwardly, the radius increases while the manifold heightdecreases. The manifold chamber M can be configured so that the heightH₁, H_(x), H_(y), . . . , H₂ decreases at a rate which maintains theface area of the annular passage substantially uniform from the inlet Ito the outer perimeter outlet O of the manifold, yielding asubstantially linear radial flow velocity across the face of themembrane filter 205.

[0124] In this regard, still referring to FIG. 9, the maximumtheoretical radial flow area of a round manifold inlet I can be definedas the circumference (2πR₁) multiplied by the height of the manifoldchamber H₁. In this instance, 2πR₁H₁ defines the total circumferentialarea of the manifold inlet I. The maximum circumferential flow area of around manifold outlet O can be defined as 27πR₂H₂. If the outlet flowarea is to equal the inlet flow area, then the inlet and outlet areascan be expressed as:

2πR₁H₁=2πR₂H₂

R₁H₁=R₂H₂

[0125] Using this expression, the heights, e.g., H_(x), H_(y) can bedefined at their given radii, e.g., R_(x), R_(y) from the inlet I to theoutlet O. If the heights H₁, . . . , H_(x), . . . , H_(y), . . . H₂ fromthe inlet to the outlet are plotted, the resulting surface 41S would becurved, not linear. However, it has been observed that a significantlycurved lower manifold surface does not work as effectively as a linearsurface 41S. Accordingly, the present preferred embodiment contemplatesa linear or substantially or nearly linear surface 41S (which can beslightly curved) extending from the inlet to the outlet. Also, there isa minimum height H₂ of about 0.006 inch clearance for the specimenliquid to effectively flow. Based on this requirement, the minimum R₁can be defined as 0.006R₂/H₁ inches. With this configuration, as thespecimen liquid is drawn through the filter, the specimen liquidtraverses the front face of the membrane filter 205 in a direction thatis substantially parallel to or approaching nearly parallel to the frontface of the membrane filter, creating the desired shearing action.

[0126] Empirical study has revealed that for a linear conical surface41S, the area of the outlet O preferably should be less than or equal tothe maximum area of the inlet I. That is, R₁H₁ R₂H₂. For example, theexemplary manifold can have the following dimensions (all units here inmm): R₁=1.24, H₁=1.32, R₂=10.00, H₂=G=0.15. The maximum inlet area wouldthus be 3.27π mm² and the outlet area 3.00π mm², which is slightly lessthan the maximum inlet area, but greater than the average inlet area,which can be defined as 50% of the maximum inlet area (1.64π mm²). Thus,the outlet area can fall between the maximum inlet area and the averageinlet area. Another example can have the following dimensions (all unitshere in inches): R₁=0.040, H₁=0.060, R₂=0.400, H₂=0.006. The maximuminlet area would thus be 0.00487π in², which is equal to the outletarea.

[0127] In summary, the manifold chamber M that confronts thesubstantially flat membrane filter should have a shallow, funnel-shapedconfiguration and a peripheral outlet so as to create a substantialradial flow across the outer surface of the membrane filter. The radialflow creates a shearing action that washes or flushes away anyparticulates that are relatively weakly attached so as to leave a verythin layer of particulates—a monolayer—on the surface of the membranefilter.

[0128] LBP Device and Method

[0129] FIGS. 11-57 illustrate a preferred embodiment of an LBP deviceaccording to the present invention. The LBP device is an automatedmachine for preparing slides for viewing, imaging or optical analysis.The LBP device can use the above-described dual flow filtering system(FIGS. 6, 7a, 9) to collect monolayers or thin layers of cells andtransfer them onto slides.

[0130] Referring to FIG. 11, the illustrated embodiment of the LBPdevice can be compartmentalized into at least six discrete processingstations: data acquisition station (bar code reader) 230; uncappingstation 400; primary stirring station 500; filter placement station 600;specimen acquisition station 700; and re-capping station 800. These sixstations are structured for parallel processing, meaning that all thesestations can operate simultaneously and independently of the other. TheLBP device also includes a separate data reading station, a slidepresentation station, a slide handling station, and a cassette handlingstation, all of which can be incorporated as an integrated system 900.The LBP device further includes a transport mechanism 240 for moving thespecimen containers to the various operating stations. It can furtherincorporate an auto loading mechanism 300 that automatically loads andunloads specimen vials onto and from the transport mechanism. Allstations are computer-controlled. FIG. 11a shows the operating sequenceof the LBP device. This is the top-level table from which the operatingsoftware is structured.

[0131]FIG. 12 shows the basic structural elements of the LBP device,namely a frame 260 preferably made of extruded aluminum, preferably oncasters (not shown) for mobility, and a machined aluminum base plate 262supported by the frame and on which the main operating mechanisms aremounted. Beneath the base plate is a compressor 264 for supplyingcompressed air for powering some of the components; a vacuum pump (notshown) which provides a vacuum source for various components; stainlesssteel shelves for holding the vial trays used in the auto loadingmechanism 300; and electrical components, including power supplies andcontrollers, and miscellaneous equipment. A compressor would not berequired if electrically-powered actuators were used instead ofair-powered actuators. A user interface, e.g. a touch-sensitive LCDdisplay (not shown), is mounted to the left of the transport mechanism240 and gives the technician control over machine operation beyond thenormal automated processing protocols. See FIG. 25, which shows examplesof a log-in screen (top) and a navigation screen (bottom) as they mightappear on the user interface. Of course, other screens would bepresented to the user as he/she interacts with the user interface.

[0132] An “economy” version of the LBP device can take the form of acounter-top model for processing a more limited number of specimens at atime. In such a model certain components can be eliminated, such asframe 260 and auto loading mechanism 300, while other components can bescaled back, such as the capacity of filter placement station 600.External sources of vacuum and compressed air could be used to powersuch a device, while other components (power supplies, controllers,etc.) could be repositioned to one or more modules adjacent to or on amodified machine base plate. Various ways of implementing thesemodifications will be readily apparent to those skilled in the art.

[0133] Transport Mechanism

[0134] Referring to FIG. 11, the transport mechanism 240 comprises anendless link-belt conveyor 242 driven by a stepper motor (not shown)around precision sprockets 242, 244. The conveyor has a plurality ofreceptacles or carriers 246, linked by pins 248, for receiving acorresponding number of specimen vials. The illustrated embodiment inFIG. 11 has 30 receptacles, numbered 1 through 30. Depending on thesample vial size and the length of the conveyor, the LBP device can usefewer than or greater than 30 receptacles, as desired or feasible,sufficiently long to permit all processing to be completed in a singleline.

[0135] The receptacles 246 of the link-belt conveyor are guided betweenthe sprockets by pairs of guide rails 250 forming tracks, and has aconventional position correction system (not shown) to accuratelyposition the receptacles. The LBP device can track the position of eachreceptacle and step-drive or index them in a conventional manner. Forinstance, the LBP device can include linear position sensors, such asoptical sensors or a photo-interrupter on each link, that can feed theposition to a controller for registering carrier position and preciselyindexing each carrier at each of the processing stations along theprocessing path. The manner of driving the conveyor for precisealignment and positioning is conventional and thus will not be describedfurther.

[0136] The guide rails 250 that form tracks in Z and Y axes engage slotsmachined in the sides of the receptacles. See, for example, FIGS. 29,33, 37 and 43. The mechanical tracks and drive sprockets can beconstructed of a self-lubricating plastic for operation without the needto add an external lubricant. The receptacles 246 each can have a window247 (see FIG. 12) for allowing access to laser or optical scanning ofthe bar code on the specimen containers. The conveyor can be hard-coatedaluminum, ®-impregnated with PTFE7 for easy cleaning. The link pins 248can be precision ground and hardened. The link pins can be axially fixedin location in the non-rotating link bore. Rotating link bores can befitted with a suitable bearing material capable of operation withoutadditional lubricant. For operator safety, the conveyor operation can beinterlocked with the cover of the machine (not shown).

[0137] The receptacles 246 are also configured so that they receive orseat the specimen vials in a particular orientation. That is, thespecimen vials and the receptacles are complementarily configured orkeyed so that the vials can only be seated in the receptacles in aparticular orientation. For example, the vials can be “D” shaped, namelyhaving a flat side (see FIGS. 2a, 2 b), and the receptacles can be “D”shaped so that the flat sides align with each other. In this way thevials do not rotate relative to the receptacles, while allowingunrestricted vertical movement relative to the receptacles. In additionto the D shape, each vial can have a bottom notch 25 (see FIG. 2a), andthe receptacles can have a mating peg or stud (not shown) that keys intothe notch 25. While the illustrated notch and peg are arcuate, they cantake on other mating shapes (e.g., V-shaped).

[0138] Vial Loading/Unloading Mechanism

[0139]FIGS. 12, 13 and 14 show the automated vial loading and unloadingmechanism 300. A pivoted pick-and-place arm 304 is mounted on anelevator carriage 306 driven by a vertical (Y-axis) lead screw motor 308atop a vertical standard 310. Arm 304 has a conventional electrically-or pneumatically-operated jaw-type gripper 312 adapted to grasp and movespecimen vials 10 in three degrees of freedom. Arm motion in horizontalplanes is afforded by lateral lead screw motor 314, which is pivotallymounted in a clevis-type bracket 316 to elevator carriage 306. Insteadof a jaw-type gripper as shown, the pick-and-place arm can be equippedwith a conventional pneumatically operated suction-head type gripper asshown in FIG. 15. Such a gripper has a silicone rubber bellows 318 whichseals against the cover 30 of a vial when placed against the cover andsubject to suction through a suction line 320. Whether mechanical orpneumatic, actuation of the gripper is accomplished through theprogrammed operation of the machine as is understood by those skilled inthe art.

[0140] Referring to FIGS. 17-20, specimen vials 10 are stored in specialinjection molded plastic vial trays 330 that slide into the machine onshelves 320 (see FIG. 12). To avoid confusion, it should be pointed outthat FIGS. 13-15 show a different form of tray (made of stamped steel),but the operation of the mechanism that rotates the trays, regardless oftheir construction, is the same. The plastic vial trays 330 are thepreferred form, and are preferably made of polypropylene. The term“tray” as used herein is not limited to the embodiments shown, andshould be construed to cover any type of carrier, rimmed or rimless,that can support and move a generally planar array of discrete articlesgenerally in the manner described herein.

[0141] Each tray 330 has forty-one circular recesses 332 sized andconfigured to receive specimen vials 10 only in one orientation. Theupper edge of each recess 332 preferably has a beveled edge 333, whichfacilitates smooth insertion of vials. The recesses are arranged in aclose-pack array of four concentric rows, preferably as follows. Theoutermost row has sixteen recesses; the next row in has eight recesses;the third row in has nine recesses; and the innermost row has eightrecesses. The receptacles of adjacent rows are offset for closerspacing. The receptacles of the second row are radially aligned with thereceptacles of the fourth (innermost) row. The receptacles of theoutermost row are spaced at 18° on center. The receptacles of each ofthe other rows are spaced at 360 on center. Of course, other receptaclearrays could be used as long as they permit access of all vials by thepick-and-place arm 304. Each receptacle has a unique and addressablelocation, so that any vial can be accessed at will and in any sequence.

[0142] As noted above, orientation of specimen vials during theprocessing is critical, so the proper orientation of the stored vials inthese trays ensures that the pick-and-place arm 304 will properlyposition each vial in a conveyor receptacle 246. Accordingly, eachrecess 332 has at its bottom (see FIG. 19) a fixed indexing peg 334 thatis sized to fit into notch 25 in the vial. The pegs 334 are installed,e.g., by adhesive, in grooves 335 that are molded into the tray adjacentthe bottoms of the recesses 332. Some of the pegs have been omitted fromFIG. 19 for illustrative purposes.

[0143] The pegs 334 are arranged at specific angles with respect to themedian plane of the tray 330 such that each vial removed from the trayis delivered to a transport receptacle with its notch aligned with themating peg in that receptacle, and vice versa. Each of these angles isdictated by the rotational position of the tray 330 when a vial in aspecific recess 332 is to be accessed by the pick-and-place arm 304, andthe angular rotation of the pick-and-place arm from the point of vialpick-up to the point of vial placement in the conveyor receptacle 246.The determination of these angles is considered to be within theabilities of one of ordinary skill in the art.

[0144] The tray 330 also has three upstanding guide posts 336, each witha spring-loaded ball 338 at its tip, which cooperate with guides (notshown) above each shelf 302 and serve to guide the tray into the machineas it is inserted and ensure its proper orientation. The guide posts 336also serve as stacking posts when the trays are stacked for storage (seeFIG. 20), the balls 338 engaging dimples 339 (see FIG. 19) in the bottomof the superior tray.

[0145] The tray 330 also has a large flared notch 340 which is orientedtoward the machine when the tray is inserted on a shelf 302. Theinnermost portion of the notch 340 has opposed keyways 342 which areadapted for engagement by floating keys, as described below. The keywayspreferably are formed in a milled brass hub insert 343 that is recessedflush with the top of the tray and secured thereto by screws.

[0146] Referring to FIGS. 14, 15 and 15 a, a rotary outer spindle 350 isjournaled at its top and its bottom in bearings 352, 354, respectively.Outer spindle 350 engages and rotates only one tray at a time so thatthe pick-and-place arm 304 can access vials therefrom by movingdownwardly through an opening 266 in base plate 262 and past any idletrays via their homed notches 340. FIG. 14 shows the home positions ofthe trays in dashed lines, with their notches 340 aligned and embracingouter spindle 350. Spindle 350 is rotated in a precision manner from thebottom by a computer-controlled rotation stepper motor 356 and a timingbelt 358 engaging timing gears 360, 362. A downwardly facing opticalrotary position sensor 363 located over the aligned tray notches detectswhen and how far a tray is rotated from its home position and providescontrol feedback for rotation of stepper motor 356.

[0147] Within outer spindle 350 is an inner spindle 364 carrying eightpairs of opposed keys 365, one pair for each tray. The keys 365 projectfrom outer spindle 350 through opposed slots 366 in the outer spindle(see FIG. 15a, which is a sectional view through the spindles and thecenter portions of the bottom two trays). The inner spindle 364 is movedvertically within the outer spindle 350 by an internal lead screw 372.Lead screw 372 is rotated by lead screw stepper motor 374 through atiming belt 376 and timing gears 378, 380. A key “home” sensor 382 (seeFIG. 15) is located at the top of inner spindle 364 to provide areference point, i.e., when the machine is turned on, it will “home” theinner spindle to the key home sensor 382 and then reference itsmovements from there.

[0148] The even vertical spacing of the pairs of keys can be seen inFIG. 15. This spacing, or pitch, differs from the pitch of the keyways342 in a full complement of installed trays 330. Accordingly, whichkeyways are engaged by the keys depends on the vertical position ofinner spindle, and only one pair of keyways (tray) can be engaged at anytime. The enlarged view of FIG. 15a shows that the keyways 342 of bottomtray 330-1 are engaged by keys 365, while the keyways of the tray aboveit, 330-2, are not engaged by any keys. Movement of inner spindle 364 byone-eighth the pitch difference disengages one tray and engages theimmediately adjacent tray. The operation of the loading and unloadingmechanism is unaffected by the absence of one or more trays from thetray slots, which are defined by shelves 302.

[0149] When a selected tray is to be accessed by the pick-and-place arm304 (as determined by the computer controller), the lead screw motor 374moves the inner spindle the appropriate distance so that the appropriatekeys engage the keyways of the selected tray. The rotation motor 356then rotates the keyed tray to the proper angular position so the arm304 can access a particular recess 332. The superposed arrangement ofthe trays, the way in which a selected tray is accessed by the gripper312 through the flared notches 340 of superior trays, and the close-packspacing of the recesses 332 in each tray make for an extremely compact,high capacity and efficient vial handling system that is readilyincorporated into the compact base of the LBP device.

[0150] In the embodiment shown, the LBP device can accommodate up toeight trays holding forty-one specimen vials each. One of the forty-onerecesses can be reserved for a cleaning vial, which would contain acleaning solution and be run through the LBP device to clean the variousparts of the device that normally come into contact with specimen fluid.Alternatively, the forty-first vial could contain a typical controlspecimen for calibration purposes. Thus the LBP device can accommodateup to at least 320 vials containing specimens to be processed. Thedevice is therefore capable of operating continuously unattended for along duration—at least eight hours—so that specimen processing can becarried out even when laboratory personnel are not normally present,such as at night.

[0151] When the trays 330 are bar-coded or otherwise labeled withmachine-readable identifying data, they can be used in an automatedstorage device that can access a particular tray on command. Thetray-identifying data can be input into the integrated data managementsystem so that the location of any specimen vial in tray storage can bereadily ascertained.

[0152] A cost reduction in tray-based storage of specimen vials can beachieved by using a liner-type system in conjunction with trays 330. Forexample, vials can be supported and stored in thin sheet-like liners(not shown) that conform to trays 330 and slip readily into recesses332. The liners are stiff enough to be self-supporting when fullyloaded, can be stacked, and can be housed in wheeled carts for ease ofmobility.

[0153] Data Accessioning and Specimen Management

[0154] It is, of course, important to keep track of each specimen vialand the specimen slides produced from each vial. Accordingly, the LBPdevice typically communicates with the integrated data management system(DMS) 104 through an accessioning station 102 or other computer. FIG. 21schematically illustrates specimen vial handling and the flow of datathat is integrated into to operation of the LBP device. Thecommunication link between the LBP device and the DMS can be made viaethernet or other protocol using a direct peer-to-peer connection, orthrough a server-based network.

[0155] The specimen processing operation begins with collecting ortransferring data from the labeled specimen vial, e.g. via a bar codereader on a data entry terminal or accessioning station, to the DMS viaeither a direct connection or over a network. Specimen tracking data caninclude, for example, the patient's name, test identification (ID)number, patient data, and any special processing instructions. Forexample, the barcoded specimen vial can be linked to the patientinformation initially by a paper requisition form and subsequently by anassigned, unique numerical ID in the database. In a preferredembodiment, the patient and test information including the vial bar codecan be entered into the networked DMS database at the point-of-care site(e.g., physician's office), thereby eliminating entirely the need for apaper requisition form. U.S. Pat. No. 5,963,368 (incorporated herein byreference), which is assigned to AccuMed International, Inc. (nowMolecular Diagnostics, Inc., or MDI) discloses a similar concept asapplied to a computer-controlled instrument for analyzing biologicalspecimens (a microscope) and storing data from each analysis. The '368patent is exclusively licensed to MonoGen, Inc. (the owner of thisapplication) in the field of liquid-based cytology in combination withor for use with non-fluorescence based image analysis devices,processes, systems and/or instruments. MonoGen's commercially availablepathology work station and data management system implement the conceptdisclosed in the '368 patent.

[0156] Each specimen vial includes an identification (ID) symbol orlabel (e.g., bar code) and/or a stored information label or symbol suchas a hologram or a memory chip or device. The present embodimentcontemplates reading an ID label using an optical reader, such as a barcode reader, which provides the information to a DMS for sharinginformation between different work stations or instruments at the sameor different locations, such as laboratories, doctors' offices,hospitals, or other patient care providers. FIG. 21 a depicts an overalllaboratory system wherein the DMS is expanded to link specimen/patientdata through a server to a variety of specimen processing devices and/orcomputerized work stations for fully integrated specimen management.

[0157] A separate bar code reader 230 (see FIG. 11) is mounted on theLBP machine itself, and scans all specimen vials prior to processingthrough a slit in each transport receptacle 246. Each of the transportreceptacles 246 is tracked using this symbol or code, such as a bar codethat can be read with a conventional optical reading device. The barcode readers used in the LBP device can be any commercially availabletype, such as Keyence BL-600, with a minimum BCR target code capabilityof Interleaved 2 of 5, Code 128 c, or EAN128. The bar code readerspreferably are sealed in liquid-tight enclosures for operatorprotection. After reading, specimen vial/transport receptacle ID dataare transmitted to the DMS of the host database or work station. Thehost database or local work station can then transmit back to the LBPdevice the specific processing protocol to be performed on thatindividual specimen.

[0158] Some of the most important functions of the data managementsystem (DMS) include:

[0159] Obtaining data on the patient and the specimen duringaccessioning, and making this available to each instrument as requiredto set processing parameters and to provide medical data to the slidereviewer;

[0160] Maintaining chain of custody of specimens and slides to ensuredata integrity;

[0161] Compiling data and printing required forms for regulatory,compliance, and laboratory management reports;

[0162] Generating medical reports and ensuring integrity usingsafeguarded digital electronic signatures;

[0163] Managing billing for instruments on “per use” charges;

[0164] Storing optimal processing protocols for each process andsupplying to the instrument in accordance with the specimen type and/oruser requirements; and

[0165] Facilitating remote diagnostics and repair, and providing usermanuals and troubleshooting guides.

[0166]FIG. 21b shows an example of a relational database table that canbe used to accomplish these tasks.

[0167] The DMS can provide paper-free data flow among the differentstages of the cytology process, saving a significant amount of personneltime and cost, reducing transcription errors, improving accuracy, andeliminating the space required to store paper records. By automating andmanaging data acquisition, storage and retrieval, each operation becomesmore efficient, significantly reducing the turn-around time forspecimens. Specimen quality is enhanced by automated calibration andcross-checking routines that identify potential problems early. Flexibleforeign language support for worldwide sales assists laboratories inmulticultural environments.

[0168] The DMS provides a common user interface that provides detailedinformation on the operation of each connected laboratory device andwork station, and together with online user manuals and training aidseases use and minimizes training. The DMS handles the exchange of allrelevant patient and specimen data with the users' own LIS (or otherdata management systems) through a provided software interface.Moreover, remote instrument diagnostic capabilities ensure maximuminterruption-free operation. The reduction in paperwork, readycross-compatibility with other instruments and existing computernetworks, and integration with the central hospital or laboratoryinformation system provides significant user benefits.

[0169] In typical operation, the laboratory: (1) receives a requisitionfrom the healthcare provider along with the pre-bar-coded specimen vial,(2) assigns a unique ID number (accession number) to the specimen, and(3) based on information on the requisition, enters a specific LBP testID to specify the process to be used. FIG. 23 shows an example of theaccessioning (data entry) screen that is presented to the technician,into which the vial bar code, accession number and LBP process code areentered. When the specimen vial is loaded into the LBP device forprocessing, the LBP device automatically reads the bar code on thespecimen vial and transmits the bar code number (106) to the DMS, whichsends back the processing parameters for the selected test, and thenumber of slides to be produced. The LBP device returns anacknowledgment (108) and processes the specimen, making one or moreslides as instructed via the DMS. Immediately before the LBP deviceimprints a specimen slide with material filtered from a specimen vial,the LBP device reads the bar code from the pre-bar-coded slide that isto receive the specimen sample. The LBP device sends each slide bar code(110) and its associated vial bar code to the DMS which updates thepatient database with the slide bar code number, cross-references it tothe correct vial number, and signals (112) the LBP device to proceed.The LBP device then imprints a cytological sample from the specimen ontoone or more slides and readies the onboard data log for the nextspecimen to be processed. FIG. 24 shows an example of a DMS menu screenshowing data items that are now linked in the DMS database, includingthe vial number, slide number(s) and patient data. The DMS can produce aprintable report listing slide ID numbers and associated vial IDnumbers, patient data and processing protocols.

[0170] At a minimum the protocol variables include specimen mixingparameters (stirring speed and time) and filter selection. Typically,primary stirring speed can be varied from 500 rpm to 3,000 rpmselectable in 50 rpm steps. The stirring interval can be varied from 5to 120 seconds, selectable in 5 second increments. Choice of filter typeis based on average pore size diameter: either 5 micron (red housing),e.g. for non-gynecological specimens, such as sputum specimens, or 8micron (white housing), e.g. for gynecological specimens, depending onthe test protocol selected.

[0171] The LBP device is capable of processing mixed sample-runs (i.e.,runs that may include vials containing various types of specimens)interchangeably and without the need for batch processing of same-typespecimens. Specimen processing can include at least 100 differentprocessing protocols resident within the DMS and accessible to users.Predefined procedure codes (test ID's) such as the following can be usedto simplify operator input and specify which processing protocol isused:

[0172] 1 breast cyst, L

[0173] 2 breast cyst, R

[0174] 3 bronchial brushing

[0175] 4 bronchial washing

[0176] 5 bronchoalveolar lavage

[0177] 6 cerebrospinal fluid

[0178] 7 colonic brushing/wash

[0179] 8 esophageal brushing/wash

[0180] 9 gastric brushing/wash

[0181] 10 gingival (buccal) scrape

[0182] 11 gyn PAP test

[0183] 12 intestinal brushing/wash

[0184] 13 nipple discharge, L

[0185] 14 nipple discharge, R

[0186] 15 ovarian cyst, L

[0187] 16 ovarian cyst, R

[0188] 17 pericardial effusion

[0189] 18 peritoneal effusion

[0190] 19 pleural effusion

[0191] 20 rectal brushing/wash

[0192] 21 sputum, induced

[0193] 22 sputum, spontaneous

[0194] 23 urine, catheterized

[0195] 24 urine, voided

[0196] Each specimen is processed with a new filter to prevent thepossibility of cross contamination. In the present embodiment, either oftwo or more different filter types can be specified for versatility intest selection (the device's eight filter tubes allow for up to eightdifferent filter types). Processing parameters for each type of specimenpreparation can be determined remotely and in advance, and communicatedto the processing device using a bi-directional communication linkutilizing the specimen vial bar code as the key identifier. The LBPdevice can utilize default (pre-loaded into the DMS) process protocolsas well as laboratory-generated process protocols that users can add tothe DMS.

[0197] An overfilled-vial sensor (not shown) can be positioned at orjust downstream of the bar code reader 230 to detect whether anexcessive amount of fluid is present in each translucent vial. Openingand processing an overfilled vial can result in hazardous spillage orejection of biological fluid. Accordingly, if an overfilled vial isdetected, the DMS will be so notified and the complete LBP processingprotocol for that vial will be canceled, allowing the overfilled vial toproceed through the processing path unopened. Alternatively, anoverfilled condition can be sensed at the conveyor holder 246 into whichvials are loaded by the vial loading mechanism 300. If an overfilledvial is detected there, the DMS will be so notified and the loadingmechanism will be instructed immediately to return the overfilled vialto its tray 330.

[0198] A similar approach can be used to deal with other anomaliesdetected as each vial is loaded into the conveyor. For example, a sensor(not shown) can be used to detect an unreadable bar code on the vial, ordetect when a vial is improperly position in the holder 246. When anysuch condition is detected, the DMS will be so notified and the loadingmechanism will be instructed immediately to return the overfilled vialto its tray 330.

[0199]FIG. 22 is a block diagram showing the components of a generalpurpose computer system or work station 270, which can be used to runthe DMS. The computer system 270 typically includes a central processingunit (CPU) 272 and a system memory 274. The system memory 274 typicallycontains an operating system 276, a BIOS driver 278, and applicationprograms 271, such as a DMS. In addition, the computer system 270 caninclude input devices 273, such as mouse, keyboard, microphone,joystick, optical or bar code reader, etc., and output devices, such asa printer 275P, and a display monitor 275M.

[0200] The computer system or work station can be connected to anelectronic network 280, such as a computer network. The computer network280 can be a public network, such as the Internet or Metropolitan AreaNetwork (MAN), or other private network, such as a corporate Local AreaNetwork (LAN) or Wide Area Network (WAN), or a virtual private network.In this respect, the computer system 270 can include a communicationsinterface 277, such as ethernet, USB, or Firewire, which can be used tocommunicate with the electronic network 280. Other computer systems 279,such as a remote host database, other types of work stations includingautomated analyzers, and computers or databases (e.g., LIS) of ahospital, laboratory, or other medical establishment, can also be linkedto the electronic network 280. Other LBP devices, as well as other typesof specimen processing instruments (e.g., automated slide stainers andcoverslippers) 279 a can also be connected to each other and the DMS viathe network.

[0201] One skilled in the art would recognize that the above-describedsystem includes typical components of a general purpose computer systemconnected to an electronic network. Many other similar configurationscan be used to control the LBP device and its processes. Further, itshould be recognized that the computer system and network disclosedherein can be programmed and configured by one skilled in the art toimplement the methods, system, and software discussed herein, as well asprovide requisite computer data and electronic signals to implement thepresent invention.

[0202] In addition, one skilled in the art would recognize that the“computer” implemented invention described further herein may includecomponents that are not computers per se, but include devices such asInternet appliances and Programmable Logic Controllers (PLCs) that maybe used to provide one or more of the functionalities discussed herein.Furthermore, while “electronic” networks are generically used to referto the communications network connecting the processing sites of thepresent invention, one skilled in the art would recognize that suchnetworks could be implemented using optical or other equivalenttechnologies. One skilled in the art would recognize that other systemconfigurations and data structures can be provided to implement thefunctionality of the present invention. All such configurations and datastructures are considered to be within the scope of the presentinvention. In this context, it is also to be understood that the presentinvention may utilize known security and information processing measuresfor transmission of electronic data across networks. Therefore,encryption, authentication, verification, compression and other securityand information processing measures for transmission of electronic dataacross both public and private networks are provided, where necessary,using techniques that are well known to those skilled in the art.

[0203] Uncapping Station

[0204] One of the advantages of the present vial-based LBP device andsystem is that it minimizes operator exposure to the specimens, whichcan contain potential biohazards. Referring to FIGS. 26-31, the LBPdevice has an uncapping mechanism 400 that first automatically separatesthe stirrer 40 in the vial from cover 30, and then removes and discardsthe cover—all without intervention by an operator. See FIG. 26, whichshows the stirrer resting on vial ribs 26 after the cover 30 is removed.

[0205] A closed specimen vial 10 which has arrived at the uncappingstation in its transport receptacle 246 is met by an uncapping head 402which is lowered onto the cover 30 of the specimen vial. See FIGS. 27and 28. Uncapping head 402 has four tapered legs 404 that form a taperedgripping cavity having chisel-like inner edges 406 spaced and sized toprogressively tighten onto cover 30 as head 402 is lowered. Once thecover is tightly engaged by the legs, a central spindle or plunger 408is lowered into contact with the center of cover 30 and applies adownward force to the cover to cause the stirrer 40 to detach from thecover 30, as described above, and drop down in the vial onto ribs 26.Then the plunger is retracted and the uncapping head 402 is rotatedcounterclockwise (FIG. 28) to unscrew cover 30 and remove it fromcontainer 20. Thereafter the uncapping head with the removed cover inits grip moves laterally to the position shown in dashed lines 410 inFIGS. 29 and 11, and plunger 408 is again lowered, this time to ejectcover 30, which falls into a waste chute or bin (not shown) beneath theuncapping head.

[0206] Alternatively, a movable waste chute can be brought beneath theuncapping head to catch the ejected cover, so that lateral movement ofthe uncapping head is not required. Covers are not reused to eliminatethe possibility of cross-contamination.

[0207] The plunger 408 is driven by a pneumatic cylinder 412, mounted onan L-bracket 415 at the top of the uncapping head, that can apply aforce on the cover of up to about 30 lbs. A coil spring 413 returns theplunger to its retracted position when cylinder 412 is deactivated. Thehead 402 is capable of applying an uncapping torque through the grippinglegs of up to about 10 lb-ft, which is sufficient to loosen the cover.The gripping legs can be of the self-energizing type so that precisealignment with the cover or small variations in cover geometry do notfrustrate their grip.

[0208] The uncapping mechanism has a mounting frame 414 supported onblocks 416 that slide laterally of the processing path on rails 418. AY-axis stepper motor 420 and lead screw 422 effect lateral motion. Theuncapping head 402 is rotatably mounted in a bearing block 424. Bearingblock 424 is secured to a C-frame 426 that is vertically slidable onmounting frame 414. Vertical movement of C-frame 426 and, hence,uncapping head 402 is effected by Z-axis stepper motor 428 and leadscrew 430. Lead screw 430 can be vertically compliant to accommodateupward movement of the cover 30 as it is unscrewed. However, it ispreferred that stepper motor 428 be actuated during the uncappingsequence so that head 402 rises at about the same rate as, but no fasterthan, the unthreading cover. Uncapping head 402 is rotatably driven byuncapper motor 432 through a gear reduction unit 433, a timing belt 434and timing pulleys 436, 438.

[0209] The uncapping head described above would also work with vialshaving a conventional “press and turn” bayonet-type coupling between thecontainer and the cover. The downward force of the plunger 408 would besufficient to release the internal antiturn lock of the coupling,allowing the gripper to rotate and remove the cover. Vials having coversthat do not require rotation for removal, e.g., a snap-on cover, wouldrequire a differently designed uncapping head, tailored to the type ofcover connection involved.

[0210] Alternatives to the above-described plunger 408 can be employedat or upstream of the uncapping station for applying the requiredexternal force to the covered vial to effect separation of the stirrerfrom the cover. For example, a cam, lever arm or other movablemechanical element can contact and press down on the cover.Alternatively, an abrupt upward external force can be applied to thevial to yield an acceleration force that overcomes the frictionalretention force between couplers 35 and 47, effectively pulling thestirrer out of engagement with the cover. This can be done by, e.g.,moving the closed vial rapidly downwardly to rap the bottom of thecontainer 20 against a rather hard surface, e.g., by mechanically and/orpneumatically thrusting the closed vial into the transport carrier 246that will hold the vial during the subsequent processing steps, or bydropping the vial down a chute into the carrier a sufficient distance todislodge the stirrer. Another way to exert an abrupt upward externalforce on the vial is to strike the bottom of the container 20 with astriking member. This can be accomplished by, e.g., cradling thecontainer 20 and momentarily thrusting a striker against the bottom ofthe container, e.g. through a bottom opening in the vial carrier 246, bypneumatic and/or mechanical means. The design of these and othervariants of suitable automated mechanisms for accomplishing these tasksis within the grasp of those skilled in the mechanical arts.

[0211] Preprocessing (Primary Stirring) Station

[0212] After uncapping is completed, the transport mechanism indexes thespecimen container to a station where preprocessing occurs. Thepreprocessing station is the location at which preprocessing operations,such as specimen dispersal within its container, are performed prior tothe container and its specimen moving to the specimen acquisitionstation. The preprocessing station typically performs a dispersaloperation. In the preferred embodiment, the dispersal operation isperformed by a mechanical mixer, which rotates at a fixed speed and fora fixed duration within the specimen container. In this example, themixer serves to disperse large particulates and microscopicparticulates, such as human cells, within the liquid-based specimen byhomogenizing the specimen. Alternatively, the specimen may containsubcellular sized objects such as molecules in crystalline or otherconformational forms. In that case, a chemical agent may be introducedto the specimen at the preprocessing station to, for example, dissolvecertain crystalline structures and allow the molecules to be dispersedthroughout the liquid-based specimen through chemical diffusionprocesses without the need for mechanical agitation. In this example,the chemical preprocessing station introduces its dispersing agentthrough the preprocessing head.

[0213] In the illustrated preferred embodiment preprocessing occurs atthe primary stirring station 500, which uses a specified or instructedstirring protocol to stir the specimen, if needed, using the stirrer 40in the container, at a specified speed (rpm) for a specified duration.The stirring protocol chiefly depends on the specimen, as describedabove, and is normally intended to disaggregate any mucous material anddisperse it and/or other particulate material in the specimen liquid.

[0214] Referring to FIGS. 32-35, the primary stirring station 500 has astirring head 502 in the form of an expanding steel collet. The colletis formed at the lower end of a shaft 503 which splits into six flexiblefingers 504 defined by six equally spaced slits 506. Shaft 503 isrotatable in a bearing block 508 secured to a C-frame 510 that isvertically slidable on a mounting frame 512. Vertical movement ofC-frame 510 and, hence, stirring head 502 is effected by a Z-axisstepper motor 514 and a lead screw 516. Stirring head 502 is rotatablydriven by a stirring motor 518 through a timing belt 520 and timingpulleys 522, 524.

[0215] The inner surfaces of the collet fingers 504 taper uniformlyinwardly toward the lower end of the collet. A central plunger 526,movable vertically by a pneumatic cylinder 528 atop a bracket 530,expands the fingers 504 outwardly when it descends and encounters thenarrowing passage defined by the tapering fingers. Thus the diameter ofthe lower end of the stirring head (collet) 502 increases when theplunger descends. This end is sized to fit loosely but closely withinthe annular wall 47 at the top of stirrer 40 when the collet is notexpanded. When plunger 526 descends, the fingers 504 expand outwardly towedge against the inside of wall 47, in manifold M, securely engagingthe stirrer.

[0216] In operation, the stirring head 502 is first lowered so that thecollet enters the manifold M. The dashed motor and bracket lines inFIGS. 33 and 34 indicate this lowered position. Then plunger 526descends to lock the stirring head to the stirrer. Then the steppermotor 514 is operated to slightly raise the stirring head and theattached stirrer 40. This vertical movement need only be very small,such as 0.050 in., just to free the stirrer from the ribs 26 and preventinterference with the container during stirring. Then DC stirring motor518 is operated in accordance with the specimen-specific stirringprotocol. Stirring speed can vary, and is usually in the range of about500 rpm to about 3,000 rpm. The stirring time can vary from about 5seconds to about 90 seconds. The base or bottom wall 41 of the stirreracts as a slinger to thrust any liquid that may rise along the stirreragainst the container wall, and prevents the escape of liquid from thecontainer. Withdrawing the plunger 526 from the collet releases thestirrer 40 from the collet 502 so the specimen container can move on tothe next station.

[0217] A contracting collet could be used instead of expanding collet502. In that case, the collet fingers would fit around the outside ofannular wall 47, and would be squeezed together to clamp around the wallby a descending sleeve that surrounds the fingers.

[0218] Filter Placement Station

[0219] At the filter placement station 600 an appropriate filterassembly F (see FIG. 5) is loaded into the open manifold M at the top ofthe stirrer 40. Filter assemblies can come in different filterconfigurations for automated machine recognition. For example, one setof filter assemblies can be colored red (5 micrometers), another setwhite (8 micrometers), each having different filtering properties, and acolor sensor can detect which type of filter is before it and cause theproper filter to be loaded. The filter assemblies are dispensed by apusher from a magazine having multiple filter tubes.

[0220] FIGS. 36-40 show the structure and operation of the filterplacement station. Referring to FIGS. 37 and 40, a filter dispensinghead 610 comprises a filter magazine in the form of a turret 612rotatable on a spindle 614 by a stepper motor 616. Vertical post 611provides the main support for the turret. Turret 612 has a top supportplate 618 with eight equally spaced holes 620 near its periphery, eachhole opening through the edge of the plate 618 with a slot 622. A bottomguide plate 624 on spindle 614 has a similar arrangement of holes thatare aligned with the holes and slots in the top support plate.

[0221] Eight steel filter tubes 626, each having an upper supportshoulder 628, are supported vertically in holes 620 and the alignedholes beneath them, with shoulders 628 resting on the top of top plate618. Each filter tube 626 has a full-length slot 630, and its bottomportion is split into four springy fingers 632 by slots 634. Just abovethe bottom end the fingers 632 curve inwardly, forming rounded innershoulders 636 against which a filter assembly F rests. The filter tubeis dimensioned such that the shoulders 636 keep up to a full stack offilter assemblies F from falling out of the tube, but deflect to allow afilter assembly to pass when the stack is pushed downwardly withoutdamage to the filter assembly. Fingers 632 thus form a springy choke.

[0222]FIG. 39 shows the position of the filter magazine 612 in relationto the processing path and the adjacent processing stations, namely theprimary stirring station 500 to the left, and the specimen acquisitionstation 700 to the right, all located on one side of the processing pathas defined by guide rails 250. On the other side of the processing pathopposite the filter magazine 612 is the assembly that supports anddrives a pusher arm 640. This assembly comprises a support post 642supporting a Z-axis lead screw 644 driven by a stepper motor (not shown)which moves a shuttle 646 that carries pusher arm 640. A filter sensor650 positioned opposite bottom guide plate 624 monitors the passage(drop) of the lowest filter assembly F in the filter tube presented to(i.e., directly above) the specimen container. Sensor 650 also detectswhen the filter tube is empty. A second sensor 651 monitors filter type.

[0223] Filter assemblies of the same type are stacked in the properorientation, with the membrane filter side (beveled edge) facing down,in each tube. For example, 54 filter assemblies can be housed in eachtube; thus a total of 432 filter assemblies can be loaded into themagazine. Fifty-four filter assemblies can be prepackaged in a stackthat is inserted into a filter tube with a wrapper tab projecting fromslot 630, and unwrapped by pulling the tab outwardly. Alternatively,filter assemblies of the same type can be dumped onto a vibratoryfeeder, which can recognize their orientation by geometricconfiguration, and properly orient and feed the filter assemblies ontothe tubes. Several of these feeders can be used, one for each type offilter assembly.

[0224] In operation, with the pusher arm 640 in its home (top) position,indicated by the dashed shuttle outline in FIG. 38, the filter magazine612 is rotated by stepper motor 616 until sensor 650 detects thepresence of the specified type of filter assembly in the filter tubebefore it. Shuttle 646 then moves downwardly with pusher arm 640 movingthrough slot 630 to press the stack of filter assemblies in that tubedownwardly, until the lowest filter assembly drops from the tube intothe manifold M in stirrer 40. When filter drop is sensed, the shuttle646 with its pusher arm 640 stops its advance. In an alternativearrangement, a weight sensor can be used to monitor the weight of thefilter stack, and detect by weight change when a filter assembly hasdropped from the stack and when the filter tube is empty.

[0225] The use of eight filter tubes 626 in magazine 612 enablesunattended processing of all of the specimens housed in the trays of thevial autoloader 300. For a counter-top model of the type describedabove, however, a single filter tube supported in a fixed position abovethe processing path would suffice for processing specimens that requirethe same type of filter.

[0226] Specimen Acquisition and Cell Deposition Station

[0227] Referring to FIG. 41, specimen acquisition station 700 has asuction head 702 that descends to engage the upper portion of thestirrer 40. Before drawing a vacuum on the specimen through the filterassembly F, the suction head grips, slightly lifts and rotates thestirrer 40, this time more slowly than at the primary stirring station(typically no more than 500 rpm for a 5 second interval), to re-suspendthe particulate matter in the specimen liquid. The re-stir motor can bea Maxon 24 volt DC planetary gear-reduced type. Then suction is appliedthrough suction line 750 to aspirate specimen liquid from the container20 through suction tube 43, into the particulate matter separationchamber (manifold) 46 and through the filter assembly F, leaving amonolayer or thin layer of uniformly deposited cells on the bottomsurface of the filter as described above. It may also be possible torotate the stirrer slowly while the specimen liquid is being aspirated.

[0228]FIG. 6 shows how the suction head cooperates with the annular wall47 of the stirrer manifold and the filter assembly F therein. The outerportion 704 of the suction head envelops the wall 47 and has an O-ring760 that seals against the outside of wall 47. The inner portion 706 ofthe suction head has two concentric O-rings 762, 764 that seal againstthe top of filter holder 200. Suction applied through port 750 creates avacuum around central opening 204 and within filter holder 200, whichdraws liquid into the manifold 46 and through the filter 202. An O-ring766 is interposed between the inner and outer portions of the suctionhead.

[0229] Referring to FIG. 42, when aspiration of the specimen iscomplete, the suction head 702 is raised. The inner portion 706 of thesuction head is extended at the same time by action of a pneumaticcylinder (not shown) mounted above the suction head. As the suction head702 is raised, the outer portion 704 disengages from the stirrer 40, butthe filter assembly F is retained on the inner portion 706 byapplication of a vacuum through suction line 752 to the annular spacebetween O-rings 762 and 764. Thus the suction head 702 removes filterassembly F from the stirrer, and can continue to apply light suction viasuction line 750 through the filter to effect a desired degree ofmoisture control of the cellular material on the filter.

[0230] The suction head 702 then moves laterally away from the transportconveyor by pivoting 90° about a vertical axis to the cell transferposition “P” shown in FIG. 46, to position the filter assembly F over amicroscope slide S delivered from a slide cassette at slide presentationstation 900. This pivoting movement of suction head 702 can also be seenin FIGS. 11 and 39. The inner portion 706 of the suction head 702 thenmoves downwardly to press the filter against the slide S with a tampingforce in the range of 4 to 8 lbs. and transfer the monolayer of cellsthereto. The phantom lines in FIG. 42 show this change in position ofsuction head 702 and contact of the filter with slide S. Instead ofbeing pivotally mounted, the suction head 702 could be mounted forrectilinear movement to and from a different deposition site whereslides are presented, e.g., above the processing path.

[0231] Referring to FIGS. 43-46, suction head 702 is rotatably mountedon a boom 716 that also carries the re-stirring motor 718, which rotatessuction head 702 through a timing belt 720. Boom 716 is pivotallysupported about a vertical axis 721 on a slide 722, which is verticallymovable along frame support 724 by means of a Z-axis stepper motor 726and a lead screw 728. Motor 726 thus moves the entire suction headvertically. Pivoting motion of boom 716 is effected by stepper a motor717 operating through a gear train (not shown). Vertical motion of theinner portion 706 of the suction head is effected by a pneumaticcylinder and return spring (not shown) mounted above the suction head toan L-bracket 719, substantially identical to the arrangement 412, 413,415 (see FIG. 29) used to move the plunger 408 of the uncapping head402.

[0232] The frame support 724 is mounted on a slide 730 so as to bemovable laterally of the transport path. A Y-axis stepper motor 732 anda lead screw 734 effect this movement. After the slide is printed thesuction head is raised by the Z-axis motor, and the Y-axis stepper motor732 advances the entire assembly to the dashed line position “X” shownin FIG. 43. Then the suction head pivots back to its originalorientation, transverse to the transport path (position “S” in FIG. 46).The Y-axis stepper motor 732 then pulls the entire assembly back towardits original position (solid lines in FIG. 43). As the suction head 702moves (to the right as seen in FIG. 43), the still-retained filterassembly F is “scraped” off the suction head by the edge 736 of anopen-top used filter (waste) tube 738 (see also FIGS. 11 and 39). Thisleaves suction head 702 free to engage a fresh filter assembly.

[0233] The vacuum source that communicates with the suction head 702pulls a slight vacuum, e.g., in the range of 3 in. to 10 in. Hg(adjustable by a regulator), through suction line 750 to aspiratespecimen liquid and draw it through the filter assembly F. Theseparately regulated vacuum applied through suction line 752 for holdingthe filter assembly to the suction head 702 is higher, on the order of20 in. Hg.

[0234] Formation of high-quality specimens on microscope slides dependscritically on the deposition of a monolayer of cells of specifiedconcentration (i.e., number of cells per unit area) on the surface ofthe filter that will contact the slide. That, in turn, dependscritically on the aspiration rate and/or the aspirated flow volume.Since cell concentration on the filter surface is a function of thenumber of filter pores blocked by the solids suspended in the specimenliquid, the percent of flow reduction from the maximum open filtercondition correlates to the blockage or amount of accumulation on thefilter. Because of the nature of biological specimens, solid particleconcentration is a significant variable in the process and must be takeninto consideration. Also, it is important to identify the total volumeof material filtered on a real time basis for other processingoperations.

[0235] The specimen acquisition station thus further includes adeposition control system for controlling the liquid draw vacuumduration by monitoring the flow rate and/or aspirated volume. Themonitored flow rate or aspirated volume can be used to signal vacuumcut-off and/or suction head retraction, which correlates to thespecified concentration of cells collected on the membrane filtersurface. If a specified concentration factor is not achieved before aspecified volume of fluid is aspirated, the system can also issue aretract signal.

[0236] Different types of deposition control systems or modules can beused for these purposes. FIG. 47 schematically shows one such system,which has a meter in the form of a digital level detector positionedalong a fluid column. This “bubble flow” system can use sensors in theform of a plurality of LED emitters and corresponding number ofphotosensors, such as Omron sensor, EE-SPX613 GaAs infrared LED, placedalong the length of the column. Any other type of sensors may be used.Alternatively, LED sensors such as the Omron sensors mentioned above canbe used without corresponding emitters when they are positioned just atthe edge of a glass tube. The meniscus edge of the liquid in the tubediffracts the light passing through the tube, and the sensor will detectthe shifted light pattern when the rising meniscus edge reaches thesensor.

[0237] The fluid column is formed in a vertically extending transparenttube or cylinder 770, e.g., one made of Pyrex glass 9 mm in diameter by1 mm thick. The aspirated specimen fluid is drawn from the specimencontainer through the membrane filter, and pulled into the glasscylinder 770 via suction line 750 and a 3-way valve 778, by means of avacuum source 772 connected to the top of the cylinder. The sensors 774are positioned evenly along the length of the cylinder 770, preferablyat 1.5 ml capacity intervals, and are interfaced with a controller ormicroprocessor 776.

[0238] In operation, in the normal state, with no fluid in the tube 770,the sensor relay line is “low.” Vacuum begins to draw fluid into thetube through the filter, and the controller marks the beginning of thedraw sequence. When the fluid reaches the first sensor, the first sensorrelay line goes “high.” The controller marks the time it took for thefluid to reach the first sensor, indicating the nearly free-flowcondition of the filter, and the relative viscosity of the fluid in thetest. When an additional 1.5 ml of fluid is drawn into the tube, thesecond sensor relay line goes “high.” The time interval for the first1.5 ml of fluid (between the first and second sensors) is noted by thecontroller, and this becomes the reference time base. As each additional1.5 ml of fluid is drawn into the system (and is detected by succeedingsensors), the time base for that increment is computed. When theincremental time base reaches an empirically derived percentage (e.g.,120%) of the original (reference) time base, the controller indicatesthat cell collection is completed, and a stop signal is transmitted,preferably to retract the suction head 702 from the manifold in thespecimen container. The empirically derived figure mentioned above isvariable with the protocol and directly controls the cellularity of thespecimen sample.

[0239] The best approximation of the free-flow condition of the filteris obtained if the time it takes for the fluid to reach the first sensor774 is kept to a practical minimum. This can be accomplished byincorporating the first sensor into the suction head itself, asschematically illustrated in FIG. 47a. In this embodiment, inner portion706 of the suction head carries an emitter 774 a and an opposed sensor774 b, which detects the leading edge of the fluid column very close tothe filter assembly F. The outer portion 704, which has teeth 775engaged by timing belt 720 (not shown), is rotatable about the innerportion 706 (note interposed bearing 773) to rotate the stirrer (notshown) and stir the specimen prior to aspiration.

[0240] During the specimen drawing operation, the controller records thecumulative or total aspirated volume. If the cumulative volume reaches apredetermined level before reaching the predetermined flow ratereduction from the reference flow, the controller will also issue a stopsignal and a flag indicating that the stop signal issued not as a resultof desired reduced flow, but by reaching the maximum liquid draw limit.A slide formed under the flagged condition will likely form ahypo-cellular condition. The controller can imprint the slide andindicate to the DMS that a hypo-cellular condition likely exists.Accordingly, if the flagged condition exists, the controller issues asignal to purge the liquid in the cylinder 770 and initiate a seconddraw. The cylinder is purged of all liquid after each sample is taken.

[0241] Referring to FIG. 48, the deposition control system can have apurge value so that when the draw cycle is completed, the stop signalgenerated by the controller 776 will open the purge valve to vent thevacuum supply line to the atmosphere and divert the liquid remaining inthe cylinder 770 into a waste container. The cylinder 770 can bemaintained under a negative pressure. The system is then ready for thenext cycle. Specifically, the system can have a 2-way solenoid valve V-3in the suction line with one port 780 open to the atmosphere. The bottomof the cylinder 770 is connected to a valve manifold 782 with twosolenoid valves V-2, V-4. The solenoid valves can be Lee LF seriesdesigned for use in vacuum systems, 2-way valve LFVA 2450110H, vitonseal, 24 volt and 3-way valve, LFRX 0500300B, viton seal, 24 volt. The2-way valve V-4 can port the specimen liquid to the bubble flow cylinder770, or to vacuum by-pass 784. The 2-way valve V-2 can control thefilter dehydration vacuum source. FIG. 49 illustrates the valve logic.

[0242] The deposition control system can use an analog level indicatorinstead of the digital sensors 774. The analog level indicator sensescapacitance of the aspirated liquid. The difference is only in themethod of sensing the volume and fill rate of the liquid in the cylinder770. Here two spaced electrodes are used, one around the outside of thecylinder 770 and the other positioned down the center of the cylinderthe cylinder, separated from the aspirated liquid by a dielectric. Ahigh frequency, such as 10 kHz, low voltage current is applied acrossthe electrodes. Capacitance in this system is measured by a bridgecircuit, which provides an analog indication of capacitance in thecircuit. As fluid fills the column, capacitance in the circuitincreases. A 10× differential in direct capacitance is easily obtainedwith this system. Capacitance is indicated on a real time basis and canbe sampled frequently enough to provide control of the sampling system.This arrangement, like the first two, uses a computer or microprocessorand a bubble flow technology to measure the flow rate and the totalfluid volume in real time. The predetermined volume increment for thesearrangements can be in the range of about 0.1 ml to 5.0 ml, andpreferably is in the range of about 1.0 to 2.0 ml.

[0243] A different system can use an ultrasonic indicator for measuringfluid movement through a tube. The ultrasonic system uses ultrasonicwave propagation through a moving liquid. In this regard, the thirdsystem employs an ultrasonic emitter and detector clamped across theliquid draw tube (suction line 750) operating on the distal end of thefilter assembly F. This system provides a digital indication of fluidflow in the tube, the total volume aspirated through the tube beingcalculated by a flow interval calculation. It measures phase shift fromthe ultrasonic wave generator source to a detector for measuring flowspeed.

[0244] Another way to measure aspirated fluid volume and control theduration of the specimen draw is to detect the change in the weight ofthe specimen vial. This can be accomplished by using a sensor that makesa high-precision measurement of the weight or mass of the vialcontaining the specimen that is being aspirated. Vial weight or mass isrepeatedly measured at a high frequency such that the rate of change ofthe weight or mass of the vial is accurately determined. Specimenaspiration is completed when the rate of change in weight or mass hasdiminished by a predetermined amount or percentage from the initialrate. The weight sensor can be, e.g., a load cell in each conveyorreceptacle 246, or a single load cell beneath the conveyor at thespecimen acquisition head that rises to engage the container above it.In either case, the specimen acquisition head can be raised slightlyduring aspiration to unload the container so that the load cell canmeasure only the combined weight of the container and the remainingspecimen.

[0245] Although specimen acquisition preferably is accomplished throughaspiration (using a vacuum), it can also be accomplished by pressurizingthe container 20 through an appropriate head that seals against the topof the container and forces specimen liquid up through tube 43 andthrough the filter assembly by means of positive pneumatic pressure. Thefluid volume control schemes and mechanisms described above would alsowork in conjunction with such a pressurized specimen acquisition system.

[0246] The cell concentration can be selected from low to high bydefining flow control cut-off. For a typical low cellularity result, thecut-off can be 80% of the 120% reference discussed above, and for highcellularity the cut-off can be set at 60% of the reference, selectablein 5% increments. The number of slides per specimen can range from oneto three. Some of the typical default protocols are as follows:

[0247] GYN: 1,000 RPM stir, 30 second interval, 8-micrometer filter,60%—high cellularity, one slide.

[0248] Urine: 1,000 RPM stir, 20 second interval, 5-micrometer filter,70%—medium cellularity, one slide.

[0249] Lung sputum: 3,000 RPM stir, 120 second interval, 5-micrometerfilter, 80%—high cellularity, two slides.

[0250] Re-Capping Station

[0251] After completing the specimen processing cycle, the specimencontainer is resealed with the stirrer still inside the container. It ispreferred to use a thin, polypropylene-coated aluminum foil to form thenew cap, which is available in roll form. The foil is drawn across theopen end of the specimen container, thermally bonded to the container ata seal temperature of about 365° F. applied for about 3 seconds with aseal force of 3 pounds, and cut from the roll. Of course, any other typeof re-capping material can be used as long as it is compatible with thevial material and creates a safe and reliable seal. For example, a foilbacked with a thermosetting resin adhesive could be used; asticky-backed foil could be used that does not require heat to effect aseal; or a plastic seal material can be bonded to the containerultrasonically. To enhance unattended operation, an automatic threadercould be included for threading a new roll of sealing material into there-capping mechanism. Cutting caps from a roll can be eliminated ifroll-mounted pre-die-cut closures having peel-off tabs are fed to there-capping mechanism.

[0252] Referring to FIGS. 50 and 52, the re-capping mechanism 800 has aside support plate 802 secured to the machine base plate. The sidesupport plate carries a main frame 810 having a top plate 812 with slots814, 816, and two side plates 818, 820. A driver capstan 822 isjournaled in side plates 818, 820. A foil advance motor 824, mounted ona bracket 826, drives the capstan. A pressure roller 828 is pivotallymounted to the main frame 810 and resiliently engages the capstan underthe influence of a spring 830. Capstan 822 and pressure roller 828define between them a throat through which the foil runs, and haveresilient surfaces which grip the foil for positive feed. A handle 832allows the throat to be opened manually to allow the end of the foil tobe fed into the throat after first passing through slot 814. A spindle804, carried side support plate 802, supports a replaceable roll offoil.

[0253]FIG. 51 shows the foil path 834 through the throat. An L-shapedcutter 836 is pivoted at its elbow to the rear of main frame 810. Oneend of a single-acting pneumatic cutter actuator cylinder 838 is mountedon a bracket 840, and the other end of the cylinder is linked to theupper leg 842 of cutter 836. The lower leg of the cutter has a blade 844that normally rests above the foil path downstream of the throat, heldin that position by a spring 845 linked between the upper leg 842 andthe support plate 802.

[0254] A rear post 850 pivotally supports an arm 852 that extendsforwardly toward main frame 810. Arm 852 carries a heated platen 854 anda foil guide fork 856 having two tines that extend toward the throat andare spaced apart so as to allow the platen 854 to pass between them. Arm852 is kept elevated, in the rest position shown in FIG. 51, by a spring858. During the re-capping operation a single-acting pneumatic cylinder860 pulls down on the arm 852 to lower the platen 854 and the guide fork856. Note the position of a container 20 in a transport receptacle (notshown) beneath the platen 854.

[0255] In operation, the foil advance motor turns the capstan 822 tofeed a measured length of foil past the cutter blade 844, into the fork856, and to the position shown by the dashed line in FIG. 51. Aphotocell 862 detects the leading edge of the foil and signals the motorto stop. Then cylinder 838 is actuated to cut the foil, and cylinder 860is actuated to pull arm 852 down to the seal position. The cut length offoil is sandwiched between the platen 854 and the container 20, and thecontainer is sealed. After about three seconds cylinder 860 isdeactivated and the arm 852 rises, returning to its rest position. Avacuum assist (not shown) optionally may be used to help hold the cutlength of foil in position on the platen prior to sealing.

[0256] The foil caps applied by the re-capping mechanism areapproximately square in shape. The corners of the foil caps can protrudefrom the vials and interfere with other recapped vials that are returnedto the trays 330. Accordingly, a foil folding ring 870 (seen in phantomlines in FIG. 51) preferably is provided which acts to fold the edgesand corners of each foil cap down along the side of the container. Thefoil folding ring 870 preferably is mounted to act on the vial in thetransport position immediately downstream of the re-capping mechanism,i.e., position “FF” in FIG. 51, and may be mounted on the recappingmechanism itself, e.g., to main frame 810, so that actuation of cylinder860 serves simultaneously to apply a foil cap to one container and foldthe edges and corners of the foil cap of the preceding (downstream)container. Alternatively, the foil folding ring or an equivalent foilfolding mechanism can be mounted further downstream of the re-cappingmechanism so as to act independently thereof.

[0257] Foil folding ring 870 is a metal ring having an inner diameterthat is slightly larger than the outside diameter of the threadedportion of the container 20. The ring 870 is mounted on an arm (notshown) that moves downwardly when actuated to lower the ring 870 overthe upper end of the container. As the ring encircles the container, itfolds the overhanging portions 872 of the foil cap against the side ofthe container. When the ring rises after folding the foil, the containeris held in position in its transport receptacle by a pin (not shown)that is mounted on a leaf spring (not shown) and is situated in thecenter of the ring 870. The leaf spring is carried by the arm that holdsthe ring, so the pin resiliently presses down against the center of thefoil cap until the arm and the ring retract fully.

[0258] The foil seals applied to the processed containers are easilypunctured by a syringe or a pipette to obtain further liquid specimensamples. The seals are very durable, however, withstanding roughhandling and preventing leakage in low ambient pressure conditions,e.g., in aircraft flying as high as 40,000 ft. Further, the appearanceof the foil seal makes it readily distinguishable from the cover of anunprocessed vial, making handling by low-skilled operators virtuallyfoolproof. To avoid the potential of puncturing the foil sealinadvertently, the re-sealed container can be capped with an unusedscrew-on cover of a distinct color.

[0259] Slide Handling and Presentation

[0260] The LBP device can use 30 and 40 slide plastic magazines(cassettes), which can accept standard 25 mm×75 mm×1 mm and 1×3 ×0.040in. slides. Metric and inch based slides can be used interchangeably.FIGS. 52-55 show a 40-slide cassette C suitable for use in the LBPdevice. The slide cassette is in some respects similar to that disclosedin U.S. Pat. No. 5,690,892 (incorporated herein by reference), but isspecially adapted for use in other devices as well, such as an automatedstainer, an automated image analyzer, and a pathology work station, sothat the slides do not have to be unloaded and reloaded into differentmagazines for use in those devices. Machine-readable indicia on thecassette, such as a bar code or an embedded microchip, provides cassetteinformation that can be linked by the DMS to the bar codes on the slidesin the cassette so that the location and status of any cassette and anyslide in that cassette can be tracked in a laboratory system. Thecassettes are stackable for compact storage and easy retrieval.

[0261] Specifically, the slide cassette is molded of plastic and has agenerally rectangular shape with an open front 902, a rear wall 904, atop wall 906, a bottom wall 908 and side walls 910. The top wall 906bears bar-coded information 909. A guide flange 912 extends laterallyoutwardly from each side wall. Rear wall 904 has a rectangular centralopening 914 through which a slide shuttle can pass (see below) toextract and return one slide at a time. An inwardly projecting ridge 916around the central opening acts as a stop against which the slides abutwhen they are inserted into the cassette. The preferred material for thecassette is ABS plastic; alternative choices include polyurethane,thermoplastic polyester, and polypropylene. The open front face is sizedto accommodate the rear of another like cassette so as to be stackable.

[0262] The slides are supported on shelves 918 at each side of thecassette. In the illustrated embodiment there are 41 pairs of left andright shelves, and each pair (except for the top pair) supports oneslide that spans the space between the shelves. Referring to thedetailed view in FIG. 53, each shelf (except for the top and bottomshelves) has a raised top ledge 920 on which the slide rests and anunderside beam spring 922 for applying a force to pinch and therebyfrictionally restrain the slide against the top ledge directly beneathit. This arrangement keeps the slides from falling out of the cassette,even when the cassette is held face down, yet enables each slide to bemoved out of and back into the cassette by the slide presentationapparatus, described below, without blocking, scratching or interferingwith the slide-mounted specimens. Each shelf 918 also has a lead-in ramp924 which guides the slide during insertion into the cassette. Eachshelf 918 (including spring 922) preferably is integrally molded intothe cassette and is attached to both the rear wall 904 and a side wall910. However, separately fabricated springs, plastic or metal, may beinserted between the shelves instead.

[0263] Each side wall is provided with multiple drainage ports 926 whichallow fluid to drain from the cassette after removal from a stainingbath. The last (top and bottom) drainage ports 923 on each side alsocooperate with a hanger assembly of a stainer for moving the cassettefrom one staining bath to another. During the staining operation thecassette is oriented generally on its side, hung from the last twodrainage ports on the upper side. An all-plastic construction makes thecassette compatible with acid baths and all types of staining bathcompositions.

[0264] Referring to FIG. 54, rear wall 904 has two rows of apertures 927that form two integrally molded gear racks 928, which are adapted toengage pinion gears 936 (see below) for moving the cassettelongitudinally so that each slide can be accessed by the slide shuttle.Two spaced parallel racks and two pinion gears enhance the smoothnessand accurate positioning of the cassette, as compared to a single rackand single pinion. Also integral with the rear wall is a row of 40cassette position sensing slots 929 extending through the rear wall andcoincident with the positions of the slides to allow for optical sensingof each slide. Further, rear wall 904 has a row of 40 blind recesses 925(these do not extend completely through the rear wall) that allow foraccurate sensing of cassette position when it is driven via the gearracks 928.

[0265] The molded cassette preferably is supplied wrapped in sealedplastic for cleanliness, with slides installed. It is therefore wellsuited for shipping, relatively low in cost, disposable yet reusable. Ithas a high storage capacity and is stackable with others, thus providinghigh density storage for specimen samples.

[0266] Slide cassettes populated with slides are manually loaded intothe LBP device in an elevated in-feed track 930 (see FIG. 11) locatedbehind the filter loading station 600 and the specimen acquisitionstation 700. No latching is required to enter cassettes into the system.Up to ten unprocessed cassettes can be loaded in the LBP device at anyone time, but only in a single orientation. The cassettes can be markedwith a top indicator, and will not be accepted if they are installedbackwards or upside down. The cassettes are loaded with their openfronts facing to the right as seen in FIG. 11, with the lead cassettebetween vertical rails 932.

[0267] The lead cassette moves down incrementally whenever a new slideis to be withdrawn from the cassette for specimen printing. This isaccomplished by a stepper motor (not shown) driving pinion gears 936that engages the racks 928 on the back of the cassette C (see FIG. 54).When all slides in the cassette have been processed, the cassettedescends all the way to outfeed track 940, and a stepper motor/leadscrew pusher 938 moves the cassette to the right into outfeed track 940,and then retracts. Then the next cassette in the infeed track 930 isadvanced by a motor/lead screw pusher (not shown) to the front positionbetween vertical rails 932, where it is engaged by the pinion gears 936and moved downwardly until the first (lowest) slide comes into positionfor extraction. Each of the feed tracks can have a home sensor, whichcan be Omron self-contained shutter type, and a cassette full sensor,which can be Keyence fiber optic.

[0268]FIGS. 11, 56 and 57 show the slide presentation system, which usesa slide shuttle feed system 960, e.g. AM Part No. 5000-1, for extractingone slide at a time from the cassette along the X-axis and placing it ona Y-axis handler, which moves the slide to the pressing (print)position. The aforementioned U.S. Pat. No. 5,690,892 discloses a similarslide cassette and shuttle arrangement used in a pathology work station(microscope). The Y-axis handler 962 has a slide platen 964 secured to afollower 966, 967. The handler is driven by a stepper motor 970 and alead screw 972, guided along a rail 968. A slide is held to the platenunder a fixed shoulder 974 (against a spring 976) and a pivoted arm 978which is spring-biased in the counterclockwise direction as seen in FIG.56.

[0269] When the handler 962 moves to the left, arm 978 moves off anadjustable stop 980 and rotates over the slide. The full Y-axis slidetravel (shown as “T” in FIG. 57) brings the center of the slide to theprint position “P” (note the dashed line position of the slide and thehandler in FIG. 56). On its way to the print position the bar codenumber on the slide is acquired by a bar code reader 982 and transmittedto the host data base. When the print position is reached the suctionhead 702, which has pivoted along arc “A” about axis 721, lowers thefilter assembly F into contact with the slide, as described above,depositing (printing) the specimen on the slide. Vacuum on the filter ismaintained throughout the printing cycle to prevent over-hydration ofthe sample and unintentional dripping.

[0270] After printing the slide moves back to the right, pausing under afixative dispensing head 984. Here a solenoid-driven pump (not shown),such as Lee LPL X 050AA, 24V, 20 microliter per pulse, yielding 12microliters per pulse (maximum of 2 pulse/second), applies fixative tothe specimen. The total volume can be determined by the number ofsolenoid cycles. The total fixative volume dispensed is programmable in20 microliter increments. It can have a flexible connection to adispensing sapphire jet nozzle with a 0.030 in. orifice. The liquid canbe gravity-fed from a reservoir to the pump. The reservoir can be a tankand can have a “fluid low” sensor connected to the operating system.More than one fixative dispenser can be employed to provide alternativefixatives as determined by processing protocols.

[0271] After the specimen is fixed, the completed slide moves all theway to the right, where it is transferred by the slide shuttle mechanismback to its original position in the cassette. When the cassette isfully processed, the entire cassette is ejected into the outfeed track940, as described above.

[0272] A Complete Laboratory System

[0273] The present LBP device does not require that specimens bepre-processed before loading, and can automate every step of the slidepreparation process. Moreover, the device does not require the operatorto open any of the specimen containers—an important operator safetyfeature. The LBP device can automatically prepare high quality cytologyslides from all specimen types, including mucous-containing GYN andnon-GYN specimens, using the integral high-speed, high-shear mixingstation that facilitates mucous disaggregation. The incorporateddual-flow filter system allows production of slides with optimal cellseparation, cell concentration, cell dispersion, and optimalpreservation of antigens, DNA, and morphologic characteristics toenhance the performance of subsequent testing. The slide cassettes,containing up to 40 slides each, will be utilized in the followonlaboratory processing devices to avoid the labor-intensive need totransfer slides to different racks before continuing with slideprocessing. Data on the patient, the specimen, the vial, the cassetteand the slide can be transferred automatically to the LIS over theuser's network, via a DMS software interface.

[0274] The present LBP device can provide eight hours of unattendedoperation. Thus, if the operator re-loads the device before leaving forthe day, a single-shift laboratory can produce two shifts of output perday without added personnel or equipment costs. The total throughput canexceed 160,000 slides per year, at a per-test cost significantly belowthat of the current leading LBP system.

[0275] The LBP device also has the capability to process specimens forcurrent and future molecular diagnostic tests including quantitative DNAanalyses, and tests utilizing markers & probes. Features built into thedevice include the capacity to employ multiple fixative dispensers inorder to provide non-routine fixatives that may be required for specialmolecular diagnostic tests.

[0276] The complete laboratory system, illustrated, e.g., in FIG. 21a,includes a pathology review station, a computer-aided microscopy workstation used by pathologists to review specimen slides and sign outcytology cases. As with all components of the laboratory system, thepathology review stations are networked to the DMS and thereby to allother devices on the system, for rapid access to patient data andspecimen processing information. The pathology review station acceptsslide cassettes for automated loading and review of specimen slides.Computerized, fully automated image analyzers will perform quantitativeanalyses of DNA and molecular diagnostic tests, receiving theiroperating instructions and reporting their results via specimen barcodes using the integral DMS. See, for example, AccuMed/MDI U.S. Pat.Nos. 5,963,368; 6,091,842; and 6,148,096, which are incorporated hereinby reference.

[0277] The laboratory system will also include, for example, slideautostainers and autocoverslippers (and/or combination automatedstainer/coverslipper devices) controlled via the DMS that utilize thesame slide cassette as the present LBP device. Cassettes containingprocessed slides can be utilized directly in these additional deviceswithout the need to unload slides and reload them into separate racks.

[0278] The inter-connectivity and high degree of automation of theprocessing and analytical devices making up the laboratory system willenable high-quality, highthroughput specimen processing and analysis atrelatively low cost.

[0279] Industrial Applicability

[0280] The above disclosure presents a safe, effective, accurate,precise, reproducible, inexpensive, efficient, fast and convenientvial-based system and method for collecting, handling and processingliquid-based cellular specimens, providing fully integrated specimen andinformation management in a complete diagnostic cytology laboratorysystem.

1. A filter assembly for separating and collecting a layer ofparticulate matter from a liquid containing the particulate matter, thefilter assembly comprising: a holder having a base and a surroundingsidewall projecting from the base, the base and the sidewall defining anopen cavity extending from the base to the rim of the sidewall at thedistal end thereof; an inner fluid pervious medium in the cavity havingopposed inner and outer faces, the inner face facing the base; a flowopening in the holder in fluid communication with the inner face of theinner fluid pervious medium; and an outer fluid pervious mediumoverlying the outer face of the inner fluid pervious medium and attachedto the sidewall, the exposed face of the outer fluid pervious mediumadapted to collect a layer of the particulate matter, the inner fluidpervious medium being of low fluidic impedance relative to the outerfluid pervious medium so that the pressure drop across the inner fluidpervious medium is less than the pressure drop across the outer fluidpervious medium when liquid flows therethrough.
 2. A filter assemblyaccording to claim 1, wherein the outer edge of the sidewall rim ischamfered, and the outer fluid pervious medium is attached to thechamfer.
 3. A filter assembly according to claim 2, wherein the outerface of the inner fluid pervious medium is proud of the sidewall rim,and the outer fluid pervious medium is a membrane filter.
 4. A filterassembly according to claim 3, wherein the membrane filter is fused tothe chamfer.
 5. A filter assembly according to claim 1, furthercomprising a seat in the cavity that supports the inner fluid perviousmedium in spaced relation to the base so as to form a chamber that isbounded by the base, the inner face of the inner fluid pervious mediumand the sidewall, and is in fluid communication with the flow opening.6. A filter assembly according to claim 5, wherein the seat comprises anannular shoulder.
 7. A filter assembly according to claim 6, furthercomprising a central support on the base in the chamber having a distalend that engages the inner face of the inner fluid pervious medium andsupports the central portion of the inner fluid pervious medium.
 8. Afilter assembly according to claim 7, wherein the distal end of thecentral support is proud of the annular shoulder so that the centralportions of the inner and outer fluid pervious media are bowedoutwardly.
 9. A filter assembly according to claim 8, wherein the outeredge of the rim of the sidewall is chamfered, and the outer fluidpervious medium is attached to the chamfer.
 10. A filter assemblyaccording to claim 9, wherein the outer face of the inner fluid perviousmedium is proud of the sidewall rim, and the outer fluid pervious mediumis a membrane filter.
 11. A filter assembly according to claim 9,wherein the membrane filter is fused to the chamfer.
 12. A filterassembly according to claim 8, wherein the central support is hollow,the flow opening is in the base in alignment with the central supportand communicates with the interior thereof, and the central support hasat least one opening that provides fluid communication between thechamber and the flow opening through the interior of the centralsupport.
 13. A filter assembly according to claim 12, wherein said atleast one opening comprises a plurality of side openings in the centralsupport.
 14. A filter assembly according to claim 12, wherein the outeredge of the sidewall rim is chamfered, and the outer fluid perviousmedium is attached to the chamfer.
 15. A filter assembly according toclaim 14, wherein the outer face of the inner fluid pervious medium isproud of the sidewall rim, and the outer fluid pervious medium is amembrane filter.
 16. A filter assembly according to claim 15, whereinthe membrane filter is fused to the chamfer.
 17. A filter assemblyaccording to claim 16, wherein the inner fluid pervious medium iscylindrical, and the sidewall is annular and closely surrounds the innerfluid pervious medium.
 18. A filter assembly according to claim 17,wherein the holder and the membrane filter are made of polycarbonate.19. An apparatus, for use with a filter, for separating and collecting alayer of particulate matter from a liquid containing the particulatematter, the filter having a collection site adapted to collect a layerof the particulate matter, the apparatus comprising a particulate matterseparation chamber for holding the filter, the separation chamberdefined by a bottom wall with a central fluid inlet and an annular wallprojecting upwardly from the bottom wall, the separation chambersupporting the filter near its periphery on spaced supports with thecollection site facing the bottom wall, the bottom wall having aradially sloped surface facing the filter such that the distance betweenthe bottom wall and the collection site decreases from the inlet towardthe filter periphery, whereby liquid introduced to the separationchamber through the inlet can flow directly through the filter anddeposit a layer of particulate matter on the collection site, and canalso flow with particulate matter outwardly across the face of thefilter and through the spaces between the filter supports.
 20. Anapparatus according to claim 19, wherein the spaces between the filtersupports are large enough to prevent the particulate matter fromclogging the spaces.
 21. An apparatus according to claim 20, adapted forcollecting a layer of cells taken from a cytology specimen, wherein theminimum dimension of the spaces between the filter supports is 0.004 in.22. An apparatus according to claim 19, wherein the sloped surface ofthe bottom wall is substantially conical.
 23. An apparatus according toclaim 19, wherein the inlet flow area, which is defined by the productof the circumference of the inlet and the distance between the inlet andthe collection site, is substantially equal to the aggregate of theradial outflow areas of the spaces between the filter supports.
 24. Anapparatus according to any one of claims 19 to 23, for use in acontainer for holding and processing particulate matter-containingliquid and adapted to be engaged by an external manipulator while in thecontainer, further comprising a tube communicating with the separationchamber through the inlet and extending downwardly from the bottom wall,whereby the tube can contact the particulate matter containing-liquid inthe container.
 25. An apparatus according to claim 24, furthercomprising a dispersing element carried by the tube for mixing theparticulate matter containing-liquid in the container.
 26. An apparatusaccording to claim 24, wherein the external manipulator is a vacuum headfor applying suction to the separation chamber to draw particulatematter-containing liquid through the filter, and the separation chamberis adapted to mate with and seal to the vacuum head.
 27. An apparatusfor separating and collecting a layer of particulate matter from aliquid containing the particulate matter, comprising: a housing defininga separation chamber having an inlet portion and an outlet portion; anda filter in the housing having a collection site facing the inletportion and defining two flow paths between the inlet portion and theoutlet portion, one flow path directly through the filter and the otherflow path around the periphery of the filter, wherein the inlet portionhas a central inlet in a surface that faces the collection site and isradially sloped such that the distance between the sloped surface andthe collection site decreases from the inlet toward the periphery of thefilter, whereby liquid introduced to the separation chamber through theinlet flows directly through the filter to deposit a layer ofparticulate matter on the collection site, and also flows withparticulate matter outwardly across the collection site toward the edgeof the filter to wash excess particulate matter from the collectionsite.
 28. An apparatus according to claim 27, wherein the sloped surfaceis substantially radially symmetrical.
 29. An apparatus according toclaim 27, wherein the inlet flow area, which is defined by the productof the circumference of the inlet and the distance between the inlet andthe collection site, is substantially equal to the aggregate radialoutflow area at the edge of the filter.
 30. A method for collectingcells for cytology comprising passing a biological fluid containingcells through a separation chamber having therein a filter with a cellcollection site positioned transversely of the fluid flow path enteringthe separation chamber through a centrally located inlet, and divertinga portion of the fluid flow outwardly toward the periphery of the filterby juxtaposition of an inlet surface adjacent the collection site thatis radially sloped such that the distance between the sloped surface andthe collection site decreases from the inlet toward the periphery of thefilter, whereby fluid introduced to the separation chamber through theinlet flows directly through the filter to deposit cells on thecollection site, and also flows outwardly across the collection sitetoward the edge of the filter to wash away excess cells from thecollection site leaving substantially a monolayer of cells on thecollection site.
 31. A method according to claim 30, wherein the inletflow area, which is defined by the product of the circumference of theinlet and the distance between the inlet and the collection site, isequal to or greater than the aggregate radial outflow area at theperiphery of the filter.
 32. A method according to claim 30, wherein thecollection site is slightly bowed outwardly at its center, furthercomprising removing the filter from the separation chamber and pressingthe filter against a slide to flatten it against the slide and transfersubstantially all of the cells from the filter to the slide.
 33. Amethod for collecting cells from individual specimens of biologicalfluid in specimen containers, each container having therein a processingassembly comprising an open-top separation chamber, adapted to receive afilter assembly having a downwardly facing collection site, and adepending aspiration tube that extends into the specimen andcommunicates with the separation chamber through the bottom wallthereof, the method comprising, for each container, the steps of:placing a filter assembly in the separation chamber; coupling a movablesuction head to the processing assembly and the filter assembly;elevating the suction head to raise the processing assembly sufficientlyto eliminate contact of the processing assembly with the container;applying a vacuum to the filter assembly to aspirate specimen fluid fromthe container through the tube, into the separation chamber and throughthe filter until a layer of cells is collected on the filter collectionsite; uncoupling the suction head from the processing assembly; andelevating the suction head to remove the still-coupled filter assemblyfrom the separation chamber.
 34. A method according to claim 33, whereinthe suction head is coupled to the filter assembly by vacuum.
 35. Amethod according to claim 34, wherein the vacuum applied to couple thesuction head to the filter assembly is on the order of 20″ Hg.
 36. Amethod according to claim 34 or 35, wherein the vacuum applied toaspirate specimen fluid from the container is in the range of about 3″Hg to about 7″ Hg.
 37. A method according to claim 33, furthercomprising moving the suction head with the still-coupled filterassembly over a slide, and moving the suction head downwardly to pressthe filter assembly against the slide to transfer cells from the filterassembly to the slide.
 38. A method according to claim 37, furthercomprising uncoupling the filter assembly from the suction head anddisposing of the filter assembly.
 39. An apparatus for collecting cellsfor cytology from individual specimens of biological fluid in specimencontainers, each container having therein a processing assemblycomprising an open-top separation chamber, defined by a bottom wall andan upstanding annular wall and adapted to receive a filter assembly, anda depending aspiration tube that extends into the specimen fluid andcommunicates with the separation chamber through the bottom wall, thefilter assembly having a holder with a flow opening in its upper faceand a filter arrangement in the holder having a downwardly facingcollection site, the apparatus comprising: a suction head adapted to bepositioned above a container and mounted for vertical movement relativeto the container, the suction head comprising coaxial inner and outerportions, the outer portion having an annular skirt adapted to surroundand sealingly engage the annular wall of the separation chamber, theinner portion having a lower face with an aspiration suction port and aretention suction port, the inner portion being mounted for axialmovement relative to the outer portion and adapted to sealingly engagethe upper face of the holder so that the aspiration suction port is influid communication with the flow opening and the retention suction portis in fluid communication with a scaled annular area on the upper faceof the holder, a head actuator for moving the suction head vertically;and an inner portion actuator for separately moving the inner portionvertically.
 40. An apparatus according to claim 39, wherein the suctionhead is journaled for rotation about the coaxial axis to mix thespecimen in the container, further comprising a mixing actuator forrotating the suction head.
 41. An apparatus according to claim 39 orclaim 40, wherein the suction head is mounted for lateral movement awayfrom and toward the container, further comprising at least one lateralactuator for laterally moving the suction head.
 42. An apparatusaccording to claim 41, wherein the lateral movement of the suction headcomprises pivotal movement about an axis parallel to the coaxial axis.43. An apparatus according to claim 42, wherein the lateral movement ofthe suction head comprises horizontal translating movement.
 44. Anapparatus according to claim 39, wherein the annular skirt has aninternal an O-ring that seals against the outer surface of the annularwall of the separation chamber, and the inner portion has two concentricO-rings on its lower face, the inner of the concentric O-ringssurrounding the aspiration suction port, the retention suction portlying between the concentric O-rings, and the concentric O-rings formingthe sealed annular area on the upper face of the holder when in contacttherewith.